Rotavirus

29 February 2012

Key facts

  • Rotavirus is the most common cause of severe diarrhoeal disease in infants and young children globally.
  • Worldwide, rotaviruses are estimated to be responsible for approximately 453,000 deaths among children aged <5 years each year, with 95% of these deaths occurring in countries eligible to receive vaccine support from the GAVI Alliance.
  • It is also estimated that over 2 million children are hospitalized each year with pronounced dehydration from rotavirus infection.
  • Among 46 countries participating in the Global Surveillance Network for rotavirus in 2010, 40% of hospitalizations for diarrhoea among children aged <5 years were caused by rotavirus infection.
  • Severe rotavirus gastroenteritis is largely limited to children aged 6-24 months.
  • Vaccines against rotavirus gastroenteritis are available and vaccination is an important measure to reduce severe rotavirus-associated diarrhoea and mortality.
  • WHO recommends the inclusion of rotavirus vaccine in the national immunization schedules of all countries, and strongly recommends the inclusion of rotavirus vaccine in countries where diarrhoeal deaths account for 10% or more of deaths in children aged <5 years.
  • Currently, two oral, live attenuated rotavirus vaccines are available and licensed in most countries.

Transmission

  • Rotavirus is transmitted through the oral-faecal route, directly from person to person, or indirectly through contaminated objects.
  • In developing countries, three-quarters of children acquire their first episode of rotavirus diarrhoea before the age of 12 months, whereas in developed countries the first episode is frequently delayed until the age of 2-5 years.
  • In temperate climates, the incidence of rotavirus gastroenteritis typically peaks during the winter season, whereas in tropical setting rotavirus may occur year round with seasonality masked by high background levels.
  • Stool and vomitus from infected individuals are highly infectious, containing rotaviruses in very high concentrations (>1012 particles/gram).
  • Rotavirus is readily transmitted among siblings and in other settings where infants and young children have close contact.
  • Rotavirus is also a known cause of nosocomial (hospital-based) diarrhoea outbreaks.
  • The universal occurrence of rotavirus infections shows that clean water supplies and good hygiene are unlikely to have a substantial effect on virus transmission.

Symptoms

  • The incubation period for rotavirus is typically 1-3 days, with abrupt onset of fever and vomiting followed by explosive, watery diarrhoea.
  • Rotavirus diarrhoea is profuse, often leading to dehydration which can be severe, requiring hospitalization.
  • Severe rotavirus gastroenteritis is largely limited to children aged 6-24 months.

Diagnosis

  • Rotavirus can be diagnosed by detection of antigen with an enzyme immunoassay (EIA) test of a stool sample.
  • EIA tests are more sensitive than other commercially available tests.
  • A range of more advanced laboratory techniques are used for strain differentiation.

Treatment

  • Treatment is directed at managing the dehydration and electrolyte loss resulting from the diarrhoea. No specific antiviral therapy is available.
  • Community-based administration of oral rehydration solution, zinc supplementation, and when necessary intravenous fluids are part of effective case management for watery diarrhoea.
  • Dehydration is the main cause of death among children infected with rotavirus. With appropriate case management, recovery is usually complete.

Prevention

  • Rotavirus vaccines are an important measure to reduce severe rotavirus-associated diarrhoea and mortality.
  • Recent data from clinical trials, which evaluated vaccine efficacy in countries with high child mortality, has led WHO to recommend the inclusion of rotavirus vaccination of infants in all national immunization programmes.
  • Furthermore, in countries where diarrhoeal deaths account for 10% or more of deaths among children aged <5 years, the introduction of rotavirus vaccine is strongly recommended.
  • Currently, two oral, live attenuated rotavirus vaccines are available and licensed in most countries. Several other oral live vaccines are in various stages of development by vaccine manufacturers in developing countries.
  • Use of the vaccine should be part of a comprehensive diarrhoeal disease control strategy including, among other interventions, improvements in hygiene and sanitation, zinc supplementation, community-based administration of oral rehydration solution and when necessary, intravenous fluid administration.
  • In order to minimize a potential risk of intussusception, WHO recommends that the first dose of either RotaTeq™ or Rotarix™ vaccine be administered during the period of 6 weeks to 15 weeks of age. The maximum age for administering the last dose of either vaccine is recommended to be at 32 weeks of age.
  • Large safety studies with the two commercially available rotavirus vaccines, however, have demonstrated that these vaccines are safe and that an intussusception risk of the order of that which had been associated with the earlier Rotashield™ vaccine can be ruled out with confidence.
  • WHO recommends that sentinel surveillance for severe rotavirus gastroenteritis should be in place to monitor vaccine impact. Proposed strategies rely on a network of sentinel hospitals reporting to WHO, where young child with diarrhoea are tested for rotavirus infection.
  • In addition, post-marketing surveillance systems should be established to monitor possible vaccine adverse events, including intussusception. Absence of such post-marketing surveillance at the outset should not be an obstacle to introducing the vaccine.

WHO's response

  • WHO provides country-specific estimates of rotavirus mortality to Member States, to help provide the evidence necessary for vaccine policy.
  • WHO recommends the inclusion of rotavirus vaccine in all national infant immunization programmes, and provides rotavirus vaccine introduction guidelines and training materials.
  • WHO recommends surveillance to monitor vaccine impact and safety, and provides a generic rotavirus sentinel surveillance protocol and a rotavirus post-marketing surveillance manual for countries to use.
  • WHO promotes wider access to rotavirus vaccines in partnership with the GAVI Alliance, UNICEF and others.
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Last update:

25 July 2013 03:24 CEST