Monday, November 14, 2011

Rotavirus


This time in the extended series on gut infections, I will cover a virus. Up until this point all of the infectious organisms covered have been bacteria. Interestingly, while the content of our natural gut microbiome comprises a vast number of bacterial species, it is very likely that this number is miniscule compared to the number of viruses that contribute to this microbiome. Most of the virome, as it is with the bacteriome, is commensal or symbiotic with the host. Nevertheless, some gut viruses are pathogenic to the host. On a global scale, the most important of these is, by far, rotavirus.

The Pathogen. Rotavrius is a double-stranded RNA virus in the Reoviridae family. The genome is comprised of 11 segmented helices of RNA, which correspond to the genes of this virus. In total there are five species of rotavirus, designated rotavirus A though E, with A, B, and C being most important for human infections. Approximately 90% of  these infections are due to rotavirus A alone. Thus, this discussion will focus primarily on rotavirus A, although rotavirus B has caused significant outbreaks in China.

There are 3 structural viral proteins and 1 non-structural viral protein that are important factors in the infectivity, pathogenicity, and immunogenicity of this virus. Viral proteins (VP) 4, 6 and 7 are the structural proteins relevant to the above. VP4 is a protein that projects from the capsid and binds to enterocyte receptors, which induces infection of the host cell. Rotavirus infection requires the activity of a protease native to the host gut. This protease alters the structure of VP4 resulting in the newly modified VP5 and VP8 surface proteins, which then initiate infection. VP6 constitutes the primary capsid protein and is a potent antigen, which is important as a diagnostic marker and for identifying rotavirus species. VP7 is a glycoprotein found on the outer surface of the virus that constitutes another important antigen, which is highly immunogenic and responsible for long-term immune memory. Non-structural protein (NSP) 4 is an enterotoxin and is largely responsible for the pathogenicity of the infection because it is an important stimulator of diarrhea.


The virus targets the villi of the epithelium of the small intestine causing a lytic infection. Following infection, the enterotoxin, NSP4, stimulates chloride secretion from the enterocyte followed by increased water secretion into the gut, which follows the gradient. In addition, water reabsorption is inhibited and the net result is watery diarrhea. Because this is a lytic infection, some enterocyte are destroyed, which can lead to temporary nutrient deficiencies due to malabsorption.


The Disease. Simply put, it is watery diarrhea, much like we saw for cholera. However, rotavirus is quite different in terms of its disease ecology and, while potentially quite virulent in children, it is typically not as severe as outbreaks of cholera and does not typically affect adults. Nevertheless, rotavirus is the most important cause of severe diarrhea episodes in children in the world. Nausea and vomiting are also common in clinically apparent disease. Moderate fever can present in many infections, but is not always a clinical feature even in the presence of diarrhea and vomiting. The greatest threat to vulnerable children is dehydration following the large volume fluid loss. Rehydration therapy with a focus on re-establishing the electrolyte balance is imperative. The characteristic signs of the dehydration that attend the severe diarrhea are sunken eyes and cheeks and poor skin turgor. Usually 2% body fluid loss is required before dehydration is clinically recognizable. In addition to the sunken eyes and poor skin turgor mentioned above, irritability, thirst, increased heart rate and respiration, and no urine volume are also characteristic of this stage. In children, less than 10% loss of body fluid marks severe dehydration and is characterized by low blood pressure, diminished pulse, increasingly poor skin turgor, delirium, and frequent loss of consciousness. At this stage the individual is no longer eager to drink and may not even be able to do so. This constitutes a medical emergency and requires immediate oral or intravenous (usually the latter) rehydration therapy. In addition to the dehydration, malabsorption is also a common feature of rotavirus infection due to the death of  intestinal epithelial cells.

The Epidemiology and the Landscape. Rotavirus A infections are the second largest single pathogen cause of diarrhea in the world. As with all diarrhea disease, most of these clinically apparent episodes occur in children under 5 years of age, and most severe disease occurs between the ages of 6 months and 2 years. In addition to being a major contributor to overall diarrhea episodes across the world, rotavirus A infections are responsible for the most severe diarrhea episodes in the world. In communities with access to advanced hospital care, rotavirus is responsible for at least 2 million severe cases requiring hospital admission and advanced therapy and management of dehydration. Rotavirus A causes approximately 500,000 deaths per year. Most of these deaths are concentrated in resource poor geographic regions as depicted in this map by the World Health Organization:


While the mortality attributable to rotavirus follows the same lines of geography as that attributable to all other causes of diarrhea, the landscape epidemiology of rotavirus is distinctly different from the other gut pathogens we have covered at Infection Landscapes.

Rotavirus infection follows fecal-oral transmission, as have most of the pathogens covered so far in this extended series on gut infections. Rotavirus, however, is highly infectious. The infectious dose is 10 to 100 virions. Moreover, there are tens of trillions of virions shed per diarrhea episode in infected individuals. In addition, rotavirus is quite stable outside the human gut in aquatic environments. This combination of properties contributes to one of the most important features of the epidemiology of this virus: it is ubiquitous in all geographic locations where it is consistently maintained in environmental reservoirs. Furthermore, good sanitation and water infrastructure, which are usually sufficient to prevent the bacterial and parasitic gut infections of significance and thus reduce the burden of disease in all settings, are not sufficient to eliminate the burden of disease due to rotavirus in any setting. The simplicity of this epidemiology ensures ongoing infection in populations, which is, contrary to the defining paradigm of this website, irrespective of the landscape. In the absence of vaccination programs, there is little difference in the incidence of rotavirus infections by geography. There is, of course, a difference in mortality attributable to rotavirus by geography, but this is more a function of the presence of resources to treat and manage the severe dehydration that can attend the diarrhea.

Treatment. Oral rehydration salts mixed with water provide an important treatment, but are not always as effective as they are against other diarrhea, thus the particularly high rates of hospitalizations associated with rotavirus infections. The goal is to reestablish the electrolyte balance in the person suffering the diarrhea episode. In order to stave off what can develop into deadly dehydration, the individual must replace the fluid lost, AND the salts lost. This is precisely the goal of oral rehydration therapy. Packets of oral rehydration salts containing sodium chloride, potassium chloride, citrate and glucose can be obtained from almost any pharmacist or chemist in most areas of the world. These are simply mixed with water and consumed by the diarrhea-afflicted person. In addition, as much as can be tolerated by the ill person, normal nutrition intake should be maintained throughout the diarrhea episode. It may seem as though the food will go right through you, but the body does obtain some nutrients and this helps the immune system fight the infection. If dehydration is advanced, and/or if the individual is unable to keep fluids down due to vomiting, then intravenous administration of fluids will likely be necessary.

Control and Prevention. Because sanitation and water infrastructure are not significant in defining the burden of disease attributable to rotavirus, and because the virus' high infectivity and high environmental abundance are significant in defining its epidemiology, prevention of infection is largely determined by a single, highly-effective strategy: vaccination. There are 2 vaccines in use (Rotarix and RotaTeq) and both are shown to be highly effective. They are both live attenuated vaccines and administered orally. It is estimated that a little less than half the annual deaths reported each year (~ 250,000) could be prevented with the universal implementation of vaccination against rotavirus.

Here is a nice summary video by Dr. Manish Patel, a medical epidemiologist at the Centers for Disease Control and Prevention:


Interview with rotavirus expert Dr Manish Patel from GAVI Alliance on Vimeo.

47 comments:

  1. Rotavirus is highly infectious and causes severe diarrhea in infants and children under five years old. Adults are rarely affected since immunity develops with each infection. Unlike bacterial or parasitic infections, rotavirus infection cannot be treated with medications such as antibiotics. Furthermore, sanitation and clean water are not essential for eliminating this virus. Thus, prevention via vaccination or treatment with oral or intravenous rehydration are the only two effective methods. Vaccination is highly effective and as also mentioned in the movie, it has caused significant decrease in the number of deaths from rotavirus in Mexico and Brazil. These cases underline the importance of public health campaigns on vaccination and oral rehydration therapy.

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    1. Dr Gul yes the rotavirus vaccine is highly effective, I'm originally from Sudan, while growing up and visiting hospitals in the capital Khartoum the pediatric unit used to be filled to the prim with sick children, sometimes one bed has three children hooked to IV fluid and the majority of the cases were severe diarrhea and most children are between 1 to 5 years of age, some sadly die before they make it to the hospital and some develop acute severe malnutrition and dehydration.
      In 2011 Sudan was the first GAVI eligible African country to introduce the Rotavirus vaccine in their immunization schedule and they have done a good job in distributing and immunizing children through stationary and mobile clinics, last year in December I visited one of the pediatrics units in one of the busiest children hospitals in Khartoum, the unit was less crowded that I saw before the vaccine era, it was obvious there was a significant reduction in severe diarrhea cases since the introduction of the vaccine four years ago, I hope they keep it up and more countries introduce the vaccine.

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  2. Rotavirus is a good example of how important antenatal care is. I've never thought before about how fortunate we are that we receive so many vaccinations as children and never have to worry about many illnesses.
    But with the small numbers of healthcare providers or clinics in many developing countries receiving these vaccinations is a true challenge (and of course the lack of the vaccine itself).
    Infants are required to get two doses of Rotarix which I can imagine is very difficult for parents in the developing world who have many children.

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    1. I agree this vaccine is a tremendous resource. Perhaps even more valuable than the vaccine is the access to clean water, salts, and nutrients, that are unavailable in many parts of the world. The vast majority of children under the age of 5 have been infected with rotavirus at some point, and that is apparently irrespective of socioeconomic status or health infrastructure. What's interesting here then, is that the mortality as a result of diarrhea in infants varies markedly based on healthcare.
      This is compelling to me because it suggests that diarrhea treatment, and access to clean water, are much much more important than the development of a vaccine, because treatment for diarrhea is very effective and covers not just rotavirus, but the myriad other diarrheal diseases.

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  3. While rotavirus may transcend infrastructure and sanitation with it's high infectivity, one cannot deny that there is still a disparity in deaths from this illness between wealthy and poor nations. Is the answer to vaccinate everyone? Or, should public health efforts to prevent rotavirus deaths in the developing world be more focused on improving quality of life and access to health care all around? If half of the rotaviruses each year would be prevented by the vaccine, would eliminating health disparities take care of the other half?

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  4. I believe that the rotavirus vaccine is a great way to control the annual number of deaths in children due to rotavirus. Although there are a number of other factors to be considered in developing areas, vaccines seem to be a quick and sometimes less costly solution to a problem. It is interesting to me that sanitation and clean water are not necessary for the control of rotavirus as seen with almost every other gut infection. In terms of planning, it may be a lot easier and take less time to administer vaccines than it is to improve quality of life over an extended period of time. Hopefully we do not give up on improving quality of life in developing areas just because we have a vaccine to use. I think of vaccines as a temporary fix so as to prevent unnecessary deaths.

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  5. It is very interesting that infrastructure and sanitation improvements have a negligible impact on the burden of rotavirus indicating the infectivity and ubiquity of this pathogen. Luckily, we have both effective treatment and preventive measures. If widespread oral rehydration therapy and vaccination are implemented it appears we can really control the impact of this disease. It seems to me that rotavirus presents a huge opportunity for the public health field to show how the burden on a particular disease can be significantly reduced worldwide. The science is there. Now we need the advocacy.

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  6. Christopher DonnellyNovember 25, 2011 at 5:24 PM

    I too find it interesting that improvements to infrastructure and sanitation do not have a large effect on the impact of rotavirus unlike treatments for other diseases. Even with effective treatments for the disease, it is hard to make sure that the communities that need the rehydration treatments the most, like those of developing nations, are getting the adequate supplies to fight these infections. Vaccine use is a way to prevent the disease, but again in these developing nations we cannot depend on them as an effective means of prevention. We must rely on the ability to educate and inform individuals of the dangers of rotavirus and how to prevent it.

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  7. If I was to mention a virus that is highly infectious, has no defined landscape and the standard treatment of the symptoms isn't always effective you would think that this virus contributes to a larger disease burden than seen with rotavirus. This is not to say that rotavirus isn't serious but that it isn't as serious as it could be. This is probably because of the vaccine, but that would only prevent for approximately half of the deaths.

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  8. The fact that rotavirus mainly infect children rather than adults is very interesting. What makes children more inclined to being infected with this disease? The fact that this virus is so infectious is worrisome in regards to control efforts. Good sanitation and stronger infrastructures are the key factors in many infectious disease prevention, and can be very feasible in many countries with proper public health initiatives. However, if a virus like rotavirus is not controlled by those measures alone and requires further efforts such as vaccination, then many of these poorer countries will continue to struggle to decrease the epidemic. These vaccinations will cost money that many countries may not have, or may not think that it's an important expense. If efforts can be made not only to promote the use of vaccinations to control this disease, but also to provide an affordable vaccination, maybe we can see more of a decrease in the rotavirus epidemic around the world.  

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  9. The burden of disease that can be prevented by vaccination is quite interesting but I find the treatment to be even more so. Something as simple as salty sugar water can be used to prevent so much death in children that the fact that it is not more widely available is criminal. It's a shame that so many children must die from something so preventable. Perhaps instead of exporting democracy to Africa in the form of tear gas and shotgun shells we could send them something that supports life for a change.

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  10. I think the difficulty in establishing sustainable vaccination programs is being lost a bit. Rotaviruus is an excellent example because 1. infants should receive the vaccine within the first few months of life and 2. as Dr. Walsh mentioned it is ubiquitous. With people being born everyday there is a constant need for vaccine distribution. So to make a significant dent in mortality rates you need the proper infrastructure (ie. places for individuals to receive the vaccine, roads to allow people to get to said places, etc.) Pouring money and resources into vaccination distribution alone may save some lives for this generation but what about the next?

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  11. ...Or I should just say that you cannot think of vaccine use and development as two distinct entities.

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  12. I agree with Chris in that using vaccines may be a way to prevent the rotavirus disease, however they cannot be relied upon as an absolutely effective means of prevention. Education and exposing individuals to information about rotavirus should be the initial step in any prevention efforts. This way, we can try to prevent disease without an intervention that may be costly and possibly not very effective.

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  13. As Nicole pointed out, there are often difficulties in administering vaccines and the fact that changing landscape has such a minimal impact on outcomes makes rotavirus a very difficult organism to tackle. As we've already discussed with the case studies and examples in class, other factors that have to be taken into account are the cultural and political atmosphere of the area, hidden populations that are estranged from society and difficult to reach, immunizations requiring multiple vaccinations, and how a susceptible person may underestimate the need for a vaccine for a virus that produces diarrheal symptoms.

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  14. I agree with you Lisa. I don't think the answer is to vaccinate everyone. The impact of health disparities on mortality is undeniable. I believe improving quality of life and access to health care In the developing world would definitely reduce the incidence and prevalence of rotavirus and mortality rate.

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    1. I don’t know that the alternative option to vaccine is necessarily an improvement to quality of life concerning rotavirus in developing countries. The difference between life and death for these children is access to salt and sugar and a way of administering it. I think we are thinking along the same lines, but I believe the solution of access to care in this specific situation is more attainable than the more general- quality of life. I am not in any way implying that providing access to care for rotavirus infection will be the simplest feat, but it pales in comparison to the Goliath of QOL improvement in developing countries.

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  15. In response to Stan:

    I agree that the treatment using oral rehydration therapy (ORT) is a must especially since it can be used to treat a number of gastrointestinal diseases. When I talk to relatives in Pakistan they say that ORT is readily available at any local drug store so I think there has been an effort to export things that support life.

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  16. Waqas - ORT is readily available in Pakistan, what about the rest of the world?

    Nicole brings up a valid point about vaccination, if we can't get the vaccination to children. When we talk about infrastructure in regards to gastrointestinal illness we often mention the need for clean water distribution. We also need to make sure that roads are passable and villages are easy to get to so that prevention becomes a more feasible option. It will also make treat meant and surveillance easier.

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  17. In response to Anika:

    I agree that many countries do not have the resources to afford this vaccination. This is often a problem that many international public health practitioners struggle with. I remember reading an article about how Paul Farmer made a deal with a drug company in India to produce medication for TB that was affordable for the Haitian people and I wonder if something like this would be possible for the Rotavirus vaccination.

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  18. In developing countries as well as developed countries, children visiting the hospital due to diarrhea are almost always infected by rotavirus. Once infected, the outcome of severe cases is determined by the availability of rehydration, either by oral rehydration salts, if tolerated by the patient, or intravenous fluids. It is interesting to note that approximately 50% of all deaths due to rotavirus can be prevented by vaccination. Sanitation and infrastructure do not contribute as much to the burden of rotavirus as compared to other diarrheal diseases. So, how can we make more vaccines available to the poorest countries who have the largest burden of this disease?

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  19. Waqas,

    It is good to hear that OTC distribution is spreading but looking online I can see the ingredients are simply acquired and can be done by anyone with salt, sugar and water. Basic formula from wikipedia: 6 tsp of sugar, 1/2 tsp of salt, dissolved into 4.25 Cups of clean water. Seems pretty straight forward. It might be more cost effective to ship the ingredients as solids and send water filters which would help with a few problems at once. Education in this case might be very useful if the ingredients are already readily available.

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  20. I also agree with Stan in that if more developed countries focus on helping provide clean water and the simple ingredients in oral rehydration solution (sugar, salt, and clean water) many unnecessary deaths from rotavirus, not to mention other feco-orally transmitted diseases, can be prevented. Instead of exporting amunition, we may also increase the support that promotes improved sanitation and clean water that can be used to make the oral rehyhdration solution, should anyone be afflicted, to reduce the morbidity and mortality of this devastating viral infection.

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  21. In response to Nicole developing a sustainable vaccination program is a challenge in many countries. Although there may be a vaccination program in place in some countries, many undeveloped countries will not have access to this resource because of their debilitating infrastructure. In these same countries there are a lack of healthcare providers, clinics, or clean facilities to even house and administer these medications. I definitely agree that more effort needs to be concentrated on developing a program that will last through generations to come and will be able to stand in both the developed and undeveloped countries.

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  22. This blog is a great source of information which is very useful for me. Thank you very much.

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  23. This is an interesting example of the public health benefits of two of the most important clinical interventions that medicine has devised, vaccinations and oral rehydration therapy. I found an interesting article discussing some controversy surrounding a rotavirus vaccine:

    http://articles.latimes.com/2010/mar/23/science/la-sci-vaccine23-2010mar23

    That's sort of a curiosity. Less of a curiosity, and more dangerous, is the fact that rotavirus vaccine is especially seized on in the anti-vaccination community as its inventor, Dr. Paul Offit, is held as an example of the flaws in our current system of vaccine development. This discussion provides a good example of why vaccination is so important, and why it's so important to honestly and critically analyze those in the anti-vaccination community. If sanitation and infrastructure is not adequate to control rotavirus, vaccination is made so much more important. For more information:

    http://www.npr.org/2011/01/07/132740175/paul-offit-on-the-anti-vaccine-movement

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  24. Waqas and Stan,
    You guys make great points on the significance of oral rehydration therapy and the potential for OTC distribution in preventing deaths from gastrointestinal diseases. However, the places where the demand is greatest for oral rehydration therapy are also the most likely places that does not have the infrastructure there to get clean water in the first place, or to get the ingredients necessary to those areas consistently. It'd be great to see a push in that direction, but it'd still mostly be a band-aid solution. It's a little disheartening that so much of disease prevention depends on the money and stability to provide infrastructure, both of which are hard to come by.

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    1. Caleb's statement has some truth to it. When I learnt about rotavirus and Oral rehydration therapy, I was under the impression that mortality from excessive diarrhea should not be a problem anymore with the therapy, which strives to provide an osmolarity isotonic to blood osmolarity but containing a high concentration of glucose. Glucose retention is very efficient in the body, and it has the added benefit of drawing hundreds of water molecules with it as it is absorbed out of the GI tract. Going back to my point, even assuming glucose is cheap and available to people in 3rd world countries, fresh water may not be easily accessible. A friend of mine who works for the peace corp in Cameroon has to walk a mile ultimately to carry back 60 lbs of water at a time for living purposes. Depending on how much support the ill child in this case has, this will determine life or death.

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  25. This entry on the rotavirus reminds me that I often take for granted the prevalence of viral inhabitants in the human body. Moreover, I was not aware that rotavirus is the most important contributor to diarrheal events in children throughout the world. I am most interested in the fact that the transmission of rotavirus is not dependent on the environmental scene. The fact that widespread implementation of the aforementioned vaccines would most likely prevent a significant number of deaths from rotavirus infection brings to mind the geopolitical setting, which must be responsible for any barrier to such implementation. I always wonder how population control plays into the evasion of such simple solutions.

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  26. I think that Rotavirus in adults is actually more prevalent than stated in most text books, especially during peak months. Too much emphasis is placed on norovirus infection when an elderly patient is admitted to hospital with gastroenteritis and little thought is given to rotavirus. It can lead to weeks in hospital, AKI, aspiration pneumonia and be the source of outbreaks within hospital wards. Vaccinating children may also reduce the numbers in the community, or in turn more adults may present to hospital with rotavirus due to waining immunity.

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  27. @Cheryl makes an interesting point about potential of waining immunity in adults after childhood vaccination. I did some research and found a CDC report (http://www.cdc.gov/vaccines/pubs/surv-manual/chpt13-rotavirus.html) that claims "no indication of waning vaccine-induced immunity has yet been observed during the rotavirus vaccine post-licensure period." This statement should be taken with a grain of salt, however, since the vaccine has only been around for ~15 years. We will not truly know the potential for waining immunity until these infants of 10 and 15 years ago come of age.

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  28. Just for clarification, the pathogen that causes the most cases of diarrhea is norovirus, which affects both adults and children. The introduction mentioned symbiotic virions in our gut, which I had not given much thought to before when considering our microflora (information usually focuses on the bacteria).

    Regarding rotavirus, I would guess that improving sanitation and the water supply is not sufficient to significantly reduce the morbidity and mortality of rotavirus is because of its high infectivity, much like with measles.

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  29. It's amazing to see how many deaths could be prevented by universal vaccination. Interventions that are related to infrastructure and sanitation would be more difficult to implement but that it not a problem with this pathogen so I think that cost and accessibility are big barriers in the reduction of rotavirus in endemic areas.

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    1. I agree with you Sarah that universal vaccination against rotavirus should be implemented, so naturally I researched these vaccines (1).Let’s begin with some limitations. Firstly, both Rotatrix (the attenuated human rotavirus vaccine) and Rotateq (the pentavalent human-bovine rotavirus reassortant vaccine) are not to be given to infants over the age of 8 months, because their effects have not been studied in any other age group. This presents a limitation for parents who have infants over that age. Secondly, Rotatrix is administered in two doses at age 2 and 4 months, and Rotateq in three doses at age 2, 4, and 6 months. This is a large burden on parents who might not remember the exact timing, might not expect multiple doses, or might have difficulty accessing the clinic for another dose (clinic might move, patient/parent might move), especially in a poverty-stricken area. It is a concern when the child gets a rotavirus infection before the dosing is complete, because the parents may be less likely to agree to another dose if they believe the vaccine was ineffective. Third, both vaccines are administered orally, which presents a challenge for the healthcare worker administering it. Babies may spit out or vomit the oral dose, and the efficacy of such regurgitated doses was not studied. The healthcare cannot inject the vaccine, as that would invalidate the effectiveness of the vaccine. Fourth, there may be several subtypes of rotavirus circulating in a given population. The vaccine given may not be effective against all of them, leading once again to parents’ decisions to forego vaccination. Lastly, the price is not insignificant for poor countries (a full 3 doses of Rotateq costs $8 at its cheapest, a full 2 doses of Rotatrix costs $19) (2).


      There are of course, benefits of vaccinating for rotavirus using these vaccines. First, the efficacy of the two vaccines ranges from 85-98% against severe rotavirus gastroenteritis in some studies. Second, even incomplete vaccination can be protective against an infection. Third, herd immunity for older children/adults can be achieved if at least 50% of the infant population is immunized. In the case in the US, immunizing 70% of the infant population was able to largely eliminate the incidence of severe rotavirus gastroenteritis.


      (1) http://www-uptodate-com.newproxy.downstate.edu/contents/rotavirus-vaccines-for-infants?source=search_result&search=rotavirus&selectedTitle=2~81
      (2) http://www.cdc.gov/vaccines/programs/vfc/awardees/vaccine-management/price-list/

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  30. Rotavirus infection transmits through the fecal-oral route which causes severe diarrhea, especially in children under 5 years of age. The most effective way to reduce infection is through vaccination. According to the CDC, rotavirus vaccine is 85%-98% protective against severe rotavirus disease and 74%-87% protective against rotavirus disease of any severity in the first year after vaccination. As previously mentioned in the original article above, there are two types of vaccinations; RotaTeq and Rotarix, both administered by mouth as liquid vaccines. RotaTeq is given as a 3-dose series at ages 2 months, 4 months and 6 months, while Rotarix is given as a 2-dose at ages 2 months and 4 months. Despite using vaccination as a preventative means, we should not forget that good hygiene (such as washing hands with soap and water and boiling drinking water) is a key component to reduce the spread of the infection.

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    1. Harry,
      You are exactly right when you say that vaccination is the most effective way to reduce infection. In fact, since 2008, it is estimated that between 40,000-50,000 rotavirus hospitalizations of US children under 5 have been eliminated yearly. That is astounding!

      The CDC now includes the rotavirus vaccine as one of the routine vaccinations given to US infants. With that in mind, a few things should be noted about these vaccines. First, they are both live vaccines. Hence, prescribers should use caution when considering vaccination of any child with a potentially compromised immune system (ie. the rotavirus vaccines should not be administered to infants with SCID). Also, there is a slightly higher incidence of intussusception has been seen post marketing with both Rotarix and RotaTeq. Therefore, any past history of intussusception is a contraindication for these vaccines. In addition, providers should warns parents about the potential warning signs of intussusception when giving the vaccine.

      Despite these potential adverse effects though, in general, these vaccines have been a huge success story. Our current challenge is simply providing their widespread distribution, worldwide.

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  31. Rotavirus is a viral pathogen known for causing a deadly-diarrhea in individual infected. Rotavirus incidence is tied together with sanitation. The efforts taken to prevent the spread of rotavirus infection have been practiced however, possibly not practiced as properly as recommended. The most affect strategy used to prevent the spread of infection is vaccination; the vaccine is a live attenuated vaccine, which is estimated that it can prevent ½ the deaths associated with rotavirus infection. Rotavirus causes an infection that can lead to death however the weight of the disease is not fully understood and the infection seems to spread with ease.

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  32. Since the advent of the vaccine, Rotavirus induces gastroenteritis cases have significantly decreased. World health organization has made recommendations to include Rotavirus vaccine in the recommended pediatric vaccination regimen.
    Rotavirus infection in the pediatric population has been implicated in the causing intussusception in which a portion of the intestine folds on itself causing a telescope appearance (inner circle and outer circle). The clinical trials results have shown cases of intussusception in individuals receiving the live rotavirus vaccine.

    https://www.merckvaccines.com/Products/RotaTeq/Pages/storageandhandling

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  33. As mentioned above, rotavirus is highly infectious but rarely affects adults. The subpopulation that experiences the greatest burden of disease is children younger than 5 years, with the most severe cases occurring between 6 months and 2 years. The mode of transmission may explain why rotavirus affects that particular subpopulation. Rotavirus is spread through fecal-oral transmission. As young children experience the diarrheal symptoms associated with rotavirus, their diapers are frequently changed. Although unintended, fecal matter may end up on a variety of surfaces. This possibility is even more common in daycares and schools. Several children in the same setting as an infected child may become infected. Young children tend to crawl, touch things and put things in their mouths. In addition, they may not practice adequate hygiene. These factors, in addition to the infectivity of the virus may explain its incidence among young children.

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    1. I also found it quite staggering of how infectious the rotavirus is in the youth of developing countries. It is interesting to note that although nearly all US children are infected before age 5, relatively very few (~20-60) deaths result. I believe that the low mortality rate may speak volumes about hygiene practices, healthcare and sanitation in the United States.

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  34. Like other RNA viruses, rotavirus has varied species that contribute different factors to the components of the disease. For example, the pathogenicity of rotavirus is controlled by (NSP) 4, an enterotoxin that is responsible for stimulating diarrhea in the affected individual. It is interesting that this disease severely affects children globally and is the source of nutrient deficiency and severe dehydration constituting a medical emergency in poor geographic regions this group. It is not much a surprise since most children are a susceptible population because of their immature immunogenicity. Dr. Patel also points out the important factors of how getting treatment quickly and efficiently is usually not a reality for many children because of inaccessibility to healthcare with the proper resources to provide oral or intravenous rehydration needed to restore electrolyte imbalance, an occurrence of this disease.

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  35. So far, this is the first virus I have read about that shows no prejudice when it comes on to whom it infects. It recognizes not the disparities that we create on individual landscapes. But alas, here come the fangs of poverty to restrain the poor and even claim lives when it pertains to treatment! It never seizes to amaze me how little it takes to save a live, yet that “little” turns out to be “much” because the poor and destitute suffer from a lack of resources. In the case of the rotavirus, we see that the most vulnerable (children) in areas with very little resources die from dehydration. There is either little access to the treatment- sodium chloride, potassium chloride, citrate and glucose needed to save their lives, or more importantly, they lack the means to administer it. When we cannot rely solely on health education and it all boils down to a lack of resources, things become increasingly difficult. I guess we now have to do the math and try to at least attain the cheaper of the two solutions: vaccines or treatment.

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  36. Once again, what used to be a common "bug" and major contributor of childhood mortality is now made almost obsolete (at least in our country) by universal vaccination. Rotavirus vaccines are usually given to infants. In New York State, the immunization schedule recommends 2-3 doses (RotaTeq, aka "RV5", requires three oral doses while Rotatrix, "RV1", requires only two). The first dose is given at age 2 months, with subsequent doses 2 months apart. As the article mentioned, both vaccines have been shown to be equally effective. For parents who are concerned about possible side effects-- rest assured, rotavirus immunization has shown to be safe! Although shedding and subsequent transmission of the virus does happen, especially during the first week after receiving the vaccination, symptoms usually do not develop in these cases. However, as health professionals, it is still a good idea to instruct caretakers and parents to thoroughly wash their hands after any contact with soiled material, such as diapers. This way, transmission of the vaccine-rotaviruses (also through the fecal-oral route) can be minimized. Lastly, one adverse event that has been associated with rotavirus vaccinations is intussusception. Intussusception is when a piece of bowel involutes, or "telescopes" on itself, causing cramping and even bloody, mucous-y stool. When severe, intussusception can cause a segment of bowel to die off. Because of this finding, infants with a history of intussusception are not recommended the rotavirus vaccine. Still, no need to worry! Herd immunity can still protect those that are not immunized!

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  37. Knowing that rotavirus is, as stated in the blog post, “the most important cause of severe diarrhea episodes in children in the world,” it is imperative for people to take precautionary measures. According to the CDC, these include good hygiene (hand washing) and cleanliness; nonetheless, these might not be enough to control the spread of the disease since the virus can spread easily even when people try very hard to keep places clean. There are also rotavirus vaccines, which can be “very effective in preventing rotavirus gastroenteritis and the accompanying diarrhea and other symptoms” (CDC 2014). In fact, the CDC recommends routine vaccination of infants with either of the two available vaccines: “RotaTeq® (RV5), which is given in 3 doses at ages 2 months, 4 months, and 6 months; or Rotarix® (RV1), which is given in 2 doses at ages 2 months and 4 months” (CDC 2014). Furthermore, as explained in the post it is crazy to know that if there is a universal implementation of vaccination against rotavirus, a little less than half the “annual deaths reported each year (~ 250,000)” could be prevented (CDC 2014). Since it often infects babies and children, it is essential for parents and guardians to know the vital importance of maintaining good hygiene and of teaching their children to wash their hands, use hand sanitizers and taking other precautionary measures to prevent infection.

    Works Cited
    Centers for Disease Control and Prevention (CDC). 2014. Prevention.
    [Internet] Rotavirus. Retrieved from http://www.cdc.gov/rotavirus/about/prevention.html.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126576/pdf/ahmt-5-143.pdf

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    Replies
    1. Well said Karla. Rotavirus is one of the few pathogens where good infrastructure is not a protective value. That said, it's hard to ignore that the developed world has an almost infinitesimally small number of cases as compared to Africa or India. Since it's not due to the good plumbing, it must be either better hygiene or most likely, wide spread vaccination. Considering that the price range for Rota Teq or Pentavalent is $50 to $110 it seems like a small amount to pay for protecting a child. On the other hand, if most o fthe world lives on $2 a day , that would equate to one years salary!

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  38. An aspect of Rotavirus that I find very interesting is how prevalent it can be with trillions of virions shed in each diarrhea episode combined with it’s resiliency in aquatic environments and in many environmental reservoirs. As noted, Rotavirus A infections are not only the main contributor of overall diarrheal episodes worldwide but also liable for more severe diarrheal cases especially among children under 5. Communities holding advanced hospital infrastructure perform dehydration therapy to around 2 million severe cases that is a significant amount. I wonder how many cases do not make it to a hospital due to limited access. Given the resiliency of the virus in the environment that make hygienic sanitation and water infrastructure practices not sufficient enough to counteract the transmission of disease, vaccinations seem like the best way to prevent disease. The successes in Mexico and Brazil send a good message of the importance of vaccination; however, as portrayed in the reading vaccinations estimated to prevent a little less that ½ of deaths due to Rotavirus A. With this in mind, I think additional public health efforts such as highlighting the importance of personal hygiene for adults and children can help reduce the incidence of the disease. Furthermore, efforts could be made to make sure vaccination programs are accessible in order to have successes like Mexico has displayed. This means providing resources not only in vaccines alone but also education of the importance of vaccines, clinics (stationary or mobile), health care workers and adequate roadways. Perhaps a multifaceted approach could increase the prevented deaths to more that ½ rather than less than ½.

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  39. Since prevention seems like the only way to prevent rotavirus infections/epidemics, further vaccine development is necessary. Since the only two vaccines available are live attenuated vaccines, they require a more extensive cold chain than an inactivated vaccine would. Thus, these live attenuated vaccines have less feasibility in reaching many of the resource-poor regions which are impacted by rotavirus. Would an inactivated vaccine work for this type of virus though?

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