A new vaccine manufactured by Pune-based Serum Institute of India has shown 66.7% efficacy against severe rotavirus gastroenteritis among infants in Niger in West Africa. Results of the Phase III efficacy trial, published on March 23 in the New England Journal of Medicine, suggest the low-cost oral vaccine can be a gamechanger in the global war against the deadly virus that kills, according to the World Health Organisation (WHO), about 600 children a day — a staggering 22% of them in India.
Serum Institute of India is the world’s largest vaccinemaker, producing and selling more than 1.3 billion doses globally every year.
What is special about Serum Institute’s new rotavirus vaccine?
Rotavac, a rotavirus vaccine produced by Hyderabad-based Bharat Biotech, became part of India’s Universal Immunisation Programme (UIP) when it was introduced in 4 states in April 2016, and was subsequently extended to 5 more states last month. The key step forward in the manufacture of Serum Institute of India’s new BRV-PV vaccine — to be ultimately called Rotasiil — is that it does not, unlike Rotavac, require refrigeration, and is, therefore, easier to store in low-income countries where rotavirus poses the greatest threat to children.
BRV-PV has completed Phase III trials in Niger, and shown good efficacy in heat-challenge conditions. “This trial brings a vaccine which is adapted to African settings to those who need it most,” AFP quoted Sheila Isanaka, assistant professor of nutrition at Harvard University and co-author of the study in the New England Journal of Medicine, as saying.
Adar Poonawalla, Chief Executive Officer, Serum Institute of India, said scientists had been working on a rota vaccine for 8 years. The Institute had decided to develop a heat-stable vaccine to overcome the absence of cold chains in many poor countries, he said. GlaxoSmithKline’s Rotarix and Merck’s RotaTeq are, like the indigenous Rotavac, sensitive to high temperatures.
What did the Phase III clinical trials of the vaccine show?
The trial, funded by Médecins sans Frontières Operational Centre and Kavli Foundation, included 3,508 infants (1,780 in the vaccine group and 1,728 in the placebo group), and was conducted from August 2014 to November 2015. At 28 days after the third dose of vaccine or placebo, severe rotavirus gastroenteritis had been reported in 31 infants in the vaccine group and 87 in the placebo group — a vaccine efficacy of 66.7%.
In a previous trial in Ghana, Kenya, and Mali, the efficacy of the RotaTeq vaccine was found to be 39.4, and in a similar trial in South Africa and Malawi, the efficacy of Rotarix was found to be 61.2%. In this trial, against a higher background incidence of severe disease than in the countries in the other two trials, there were 4.30 fewer cases of severe rotavirus gastroenteritis per 100 infant-years among infants who received BRV-PV, than among those who received the placebo. The entire trial was conducted by storing the vaccine at 25 degrees Celsius, and not in a refrigerated condition. The vaccine efficacy results under such overall conditions are unique, said Dr Rajeev Dhere, Executive Director at Serum Institute of India.
What challenges does the global immunisation programme face?
According to the World Health Organisation, vaccines prevent an estimated 2 million to 3 million deaths every year, but an additional 1.5 million deaths could be prevented if the global immunisation cover improved. In 2015, an estimated 19.4 million infants worldwide did not receive routine immunisation. A special supplement to Vaccine, a peer reviewed medical journal, noted with concern that outdated vaccine supply and distribution systems were delaying and limiting the impact that vaccines have in safeguarding people’s health. According to one study in the Vaccine collection, every year, 1 in 3 countries worldwide experiences a stockout of at least 1 vaccine for a minimum of 1 month, and the problem is most pronounced in sub-Saharan Africa. Many vaccines can lose potency if exposed for too long to temperatures outside the recommended range of 2 degrees to 8 degrees Celsius. The vaccine ‘cold chain’ strives to maintain proper temperatures for vaccines from manufacturing facilities to storage facilities, health centres, and immunisation clinics.
Each year, rotavirus gastroenteritis is responsible for about 37% of deaths from diarrhoea among children younger than 5 years of age worldwide, with sub-Saharan Africa bearing a disproportionate burden. The BRV-PV vaccine has the potential to reduce this burden.
When will the vaccine be sold in India, and at what cost?
The vaccine is already licensed in India, and is under the WHO pre-qualification process. Once approved, low-income countries will be able to procure the vaccine at an affordable price and make it available to their populations. Serum Institute plans to produce around 60 million doses to begin with, and hopes to roll out the vaccine in August- September this year. The cost is likely to be under $ 2 — between Rs 100 and Rs 120 — per dose.
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