Rotavirus vaccine (RotaTeq)

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RotaTeq (Merck Sharp & Dohme)
tubes containing 2 mL suspension
Approved indication: prevention of rotavirus gastroenteritis
Australian Medicines Handbook section 20.1

Rotavirus is a leading cause of severe gastroenteritis in young children worldwide. Rotavirus-induced disease is responsible for the hospitalisation of approximately 10 000 Australian children each year. Between July 2004 and June 2005, the most prevalent serotypes in Australia were G1 (48.3%), G3 (36.7%) and G9 (6.9%), with G2 and G4 serotypes also causing some infections (less than 1%).1However, the prevalent serotype can change over time and in 2002-03, G9 was the dominant strain causing almost 75% of cases, with G1 responsible for only 11% of infections.2

This live oral pentavalent vaccine contains five types of rotavirus. The viral surface proteins correspond to human rotavirus serotypes G1, G2, G3, G4 and P[8]. The P[8] antigen was included in the vaccine to potentially provide protection against other G-serotypes that may contain P[8], for example serotype G9.

Safety and efficacy data for the vaccine were examined in a placebo-controlled trial of 68 038 babies. The vaccine was given to healthy infants with the first dose administered between 6 and 12 weeks of age then followed by two more doses at 4-10 week intervals. All infants had been immunised by the age of 32 weeks. Oral polio vaccine was not permitted to be given at the same time; however other childhood vaccines were allowed.3

Serum antibody responses were measured in a subgroup of 189 babies 14 days after the third dose. The seroconversion rates for neutralising antibody (specific to serotypes contained in the vaccine) and antirotavirus IgA were higher in the vaccine group compared to the placebo group. However, it is not known if these antibodies are responsible for protection against rotavirus gastroenteritis.

The number of hospitalisations or emergency department visits due to infections with G1-4 and G9 serotypes was evaluated. There were 383 cases in the 28 646 babies given the placebo compared to only 20 cases in the 28 488 babies given the vaccine. Depending on the serotype, the vaccine efficacy against hospitalisation or emergency department visits varied from 87.6% to 100%. Although these findings were statistically significant, the incidence of infections with some of the serotypes was very low.3

In an efficacy sub-group analysis, vaccine efficacy against G1-4 and G9 rotavirus gastroenteritis of 'any severity' was evaluated during the first rotavirus season. There were 318 cases of infection among the 2305 babies in the placebo group compared to only 83 cases in the 2207 vaccinees.3

There is an indication that the efficacy of this vaccine may decline in subsequent seasons since during the second rotavirus season the efficacy dropped from 71.3% (first and second season) to 62.6%. Protection beyond a second rotavirus season was not evaluated in these trials.

A previous rotavirus vaccine, which was shown to be highly efficacious against rotavirus infection, was voluntarily withdrawn in 1999 because of an association with intussusception in babies after the first dose. In the trial of the new vaccine, all 68 038 babies were monitored for at least 42 days after each dose for serious adverse effects. Overall, there were 30 cases of intussusception - 12 of these occurred in the vaccine group and 18 in the placebo group. Only six cases occurred within 42 days of vaccination compared to five in the placebo group. There were ten cases of rectal bleeding in the vaccine group compared to three cases in the placebo group. The number of serious adverse events (fever, vomiting and diarrhoea) and deaths were similar in the vaccine and placebo groups. Dermatitis was more common among vaccine recipients.3

This vaccine can be given at the same time as other vaccines except oral polio vaccine.

It seems likely that this pentavalent vaccine will reduce hospitalisations due to prevalent rotavirus serotypes that cause gastroenteritis in Australia. It is not known if this vaccine will be more effective than the monovalent vaccine currently being marketed.

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