Monograph: |
Rotavirus vaccine
Rotavirus vaccine (live, oral) is licensed for immunisation of infants over 6 weeks of age for protection against gastro-enteritis caused by rotavirus infection.
Rotavirus vaccine is contra-indicated in individuals with immunodeficiency and in those predisposed to, or with a history of, intussusception. The administration of rotavirus vaccine should be postponed in infants with diarrhoea or vomiting.
The rotavirus vaccine virus is excreted in the stool and may be transmitted to close contacts; the vaccine should be used with caution in those with immunosuppressed close contacts. Carers of a recently vaccinated baby should be advised of the need to wash their hands after changing the baby's nappies.
Drug Profile
Several live oral rotavirus vaccines for use in the prevention of childhood diarrhoea have been developed and some are now licensed.
A live oral monovalent rotavirus vaccine is available in the UK. Two doses are given, the first at 6 weeks of age onwards and the subsequent dose at least 4 weeks later; the course should preferably be given before 16 weeks of age, but must be completed by the age of 24 weeks. A live oral pentavalent rotavirus vaccine is available in the USA. Three doses are given, the first at 6 to 12 weeks of age and the two subsequent doses at 4- to 10-week intervals; the third dose should not be given after 32 weeks of age.
A live oral tetravalent rotavirus vaccine (RRV-TV) was formerly available in the USA but was withdrawn by the manufacturer in October 1999 after reports of intussusception associated with its use.
Adverse effects.
Rotaviruses are an important cause of severe diarrhoea in both developed and developing countries, being most prevalent among children 6 to 24 months of age. Human rotavirus diarrhoea is caused by group A, B, or C rotaviruses. Development of a suitable vaccine has been made difficult by the diversity of rotaviruses. Initial attempts at vaccine development used single bovine or rhesus monkey strains but these were associated with variable efficacy and adverse effects.
To overcome these problems reassortant rotavirus (RRV) strains were constructed. These combined animal rotavirus strains with human rotavirus genes coding for serotype-specific antigens, enabling polyvalent vaccines to be produced against the major rotavirus serotypes causing disease. One of these, a live oral tetravalent vaccine (RRV-TV) became available in the USA in August 1998 but was withdrawn from the market by the manufacturer in October 1999 after reports of intussusception (a condition when part of the intestine prolapses into the lumen of an adjacent part causing an obstruction). From September 1998 until July 1999, 15 patients with intussusception had been reported to the Vaccine Adverse Event Reporting System (VAERS), 12 of whom developed symptoms within a week of vaccination. While this evidence was considered inconclusive, further studies were expected to clarify the risks associated with routine use of this vaccine. One such study, in which 429 infants with intussusception were retrospectively analysed, found that 74 (17.2%) had received RRV-TV compared with 226 of 1763 controls (12.8%) and concluded that there was evidence of a causal relationship with the vaccine. Another retrospective study, however, found that there was no evidence of an increase in hospital admissions due to intussusception during the period of RRV-TV availability and recommended that a large, randomised, double-blind vaccine trial be performed to determine the absolute risk. Further analysis of the incidence of intussusception associated with RRV-TV has prompted discussion as to whether the absolute risk might in fact be sufficiently low that withholding the vaccine results in greater mortality than would be caused by intussusception. Such considerations have implications for the ongoing evaluation of other candidate live attenuated rotavirus vaccines in that, should cases of intussusception occur, a decision might be required as to what constitutes an acceptable rate. A number of such candidate vaccines are under development and some are now licensed.
Rotarix
Oral suspension , powder for reconstitution, live attenuated rotavirus (RIX4414 strain), net price single-dose vial (with syringe containing diluent)
Dose
by mouth infant over 6 weeks, 2 doses of 1 mL separated by an interval of at least 4 weeks; course should be completed before 24 weeks of age (preferably before 16 weeks)
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