Rotavirus is the most common cause of severe diarrheal (gastro enteritis) disease in infants and young children globally. Children under five years of age, especially those between 6 months and two years are most vulnerable to this disease. Rotaviruses are estimated to be responsible for approximately 5, 27,000 deaths each year, with more than 85% of these deaths occurring in low-income countries in Africa and Asia, and over two million are hospitalized each year with pronounced dehydration.
Among 43 countries participating in the Global Surveillance Network for rotavirus in 2009, 36% of hospitalizations for diarrhea among children aged below 5 years were caused by rotavirus infection. Rotavirus affects populations in all socio-economic groups and is equally prevalent in industrialized and developing countries. So differences in sanitation practices or water supply are not likely to affect the incidence of the infection.
The name Rotavirus comes from the characteristic wheel-like appearance of the virus when viewed by electron microscope (the name rotavirus is derived from the Latin word Rota, meaning "wheel”). Rota viral diarrhea is an infection of the stomach and bowel. It spreads when infected children do not maintain proper personal hygiene. Virus spreads by contact or airborne route. Most cases of gastroenteritis in children are mild and usually pass within 3-5 days without the need for treatment.
However, young children, particularly those under two years of age, are at risk of dehydration. So it is very important that they drink plenty of fluids. In severe cases of gastroenteritis, where there has been significant fluid loss, hospital treatment may be required so that fluid can be replaced through drips.
The first rotavirus infection tends to be the most severe because the body builds up immunity (resistance) to the virus afterwards. This is why these types of infections are extremely rare in adults. It is estimated that every child will have at least one rotavirus infection before the age of five. Most infections occur among children aged between three months and three years old.
In India, nationally representative data on the incidence of severe rota virus disease is lacking. However, studies have revealed that on an average 34% of all diarrheal hospitalizations are due to rota virus infection and the proportion of severerota viral infection has not decreased in the last few years, similar to the global trend indicating that improved sanitation and use of anti-biotics have not been effective onrota virus. The prevalence of Rota virus in new born is high in India to the extent of 73%, but these infections are normally a- symptomatic and the likelihood of acquiring infection increases with the length of stay in the hospital.
While some studies in India have found no association between rotavirus infection and time of year, most have observed an increase in rotavirus-associated diarrhea during the winter months, October to February, throughout the country. The observed proportion of rotavirus cases occurring in the cooler season has ranged from 59% to 72%.
Treatment & Prevention
No specific treatment exists for rotavirus gastroenteritis, and repeat infections are common in children. Since 2006, vaccines are available for rotavirus infection. Prior to the availability of a vaccine, almost all children became infected with rotavirus by their third birthday. Repeat infections with different viral strains were possible. After several infections with different strains of the virus, children acquire immunity to rotavirus. Adults sometimes get infected, but the resulting illness is usually mild.
Use of vaccine should be part of a comprehensive diarrhoeal disease control strategy including, among other interventions, improvements of hygiene and sanitation, administration of oral rehydration solution and overall improved case management.
A new vaccine called ROTAVAC has been developed by a joint vaccine development initiative supported by Department of Biotechnology, Government of India, the Bill & Melinda Gates Foundation, the Research Council of Norway, and the UK Department for International Development with Bharat Biotech investing on important activities towards vaccine development. ROTAVAC is an oral vaccine and is administered to infants in a three-dose course at the ages of 6, 10, and 14 weeks. It is given alongside routine immunizations in the UIP vaccines recommended at these ages.
Currently two-rotavirus vaccines are available in the international market, namelyRotarix and Rotateq. These vaccines are less effective against medically attended rotavirus diarrhea in lower income settings. Reasons for this could be high prevalence of other intestinal infections, malnutrition, tuberculosis etc. Further, the efficacy of rotavirus vaccine decreases with lower percentage of coverage under routine immunization. Improving the overall performance of the immunization system is critical to the success of any vaccine introduction.
Several rotavirus vaccines research projects are under way in India. Cost effectiveness of rotavirus vaccine has been evaluated in two separate studies. In one of the studies third stage clinical trial of ROTAVAC is over. At a price of US $ 1 (Rs. 50/- approx), the price set by Bharat Bio-Tech, cost effectiveness in terms of disability adjusted life year, satisfy the WHO/ UNICEF criteria for a cost- effective intervention.
ROTAVAC represents the successful research and development of a novel vaccine from the developing world with global standards. The clinical trial results indicate that the vaccine, if licensed, could save the lives of thousands of children each year in India.
