Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Rotarix (GlaxoSmithKline)
vials containing powder for reconstitution
Approved indications: prevention of rotavirus gastroenteritis
Australian Medicines Handbook section 20.1
Rotaviruses are a common cause of gastroenteritis in children. This can result in dehydration and, particularly in developing countries, death.

There are different strains of the virus. This vaccine has been developed from the common G1 serotype (89-12 strain). The production process results in a live attenuated vaccine which can be given orally (on the inside of the cheek).

A phase II trial in Singapore involved 2464 babies aged 11–17 weeks. They were given three different concentrations of the vaccine or a placebo. The seroconversion rate was 75–86% after a month. A second dose was then given and this resulted in 76–91% of the babies having antirotavirus antibodies one month later.1

A trial in South America gave three different concentrations of the vaccine to 1618 babies 6–12 weeks of age. Another group of 537 babies was given a placebo. Two months after the second dose of vaccine 61–65% of the babies had seroconverted. During the first year of life there were 1635 episodes of gastroenteritis but rotavirus was only isolated in 109 babies. Rotavirus gastroenteritis affected 3.58% (58/1618) of babies randomised to the vaccine group and 9.49% (51/537) of babies randomised to the placebo group. Vaccine efficacy against rotavirus gastroenteritis was calculated to be 56–70%.2

Another South American trial gave the vaccine to 31 673 babies at the age of two and four months. Compared to a control group of 31 552 given a placebo, the vaccinated babies had a significantly reduced rate of severe gastroenteritis. In the cohort of 20 169 babies followed until they were one year old, nine vaccinees needed hospital admission, compared with 59 of the placebo group. The vaccine efficacy against severe gastroenteritis was 85%.3

Adverse events which had a higher incidence with the vaccine than with placebo included irritability, flatulence, diarrhoea, reduced appetite and fever.

The vaccine can be given at the same time as other vaccines. Although it can be given with oral polio vaccine, a gap of two weeks is suggested. As viral antigen is excreted in the stools there is a potential for transmission to other people.

A different rotavirus vaccine marketed in the USA was withdrawn in 1999 after it was associated with intussusception. During the large South American study there were nine cases of intussusception following vaccination compared with 16 in the placebo group. Although the difference was not statistically significant, 56 deaths occurred after vaccination compared with 43 in the placebo group.3

The vaccine is most likely to be of benefit in communities with a high incidence of severe rotavirus gastroenteritis. Whether the multivalent vaccines under development will have greater effectiveness than this monovalent vaccine is currently uncertain.

Read about The Transparency Score manufacturer provided additional useful information

The Transparency Score ( ) is explained in New drugs: transparency', Vol 37 No 1, Aust Prescr 2014;37:27.

References

  1. Phua KB, Quak SH, Lee BW, Emmanuel SC, Goh P, Han HH, et al. Evaluation of RIX4414, a live, attenuated rotavirus vaccine, in a randomized, double-blind, placebo-controlled phase 2 trial involving 2464 Singaporean infants. J Infect Dis 2005;192:S6-S16.
  2. Salinas B, Perez Schael I, Linhares AC, Ruiz Palacios GM, Guerrero ML, Yarzabal JP, et al. Evaluation of safety, immunogenicity and efficacy of an attenuated rotavirus vaccine, RIX4414. A randomized, placebo-controlled trial in Latin American infants. Pediatr Infect Dis J 2005;24:807-16.
  3. Ruiz-Palacios GM, Perez-Schael I, Velazquez FR, Abate H, Breuer T, Clemens SC, et al. Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis. N Engl J Med 2006;354:11-22.