New Delhi:The cheapest vaccine to protect against one of the major causes of childhood diarrhoea in India entered the official immunization programme late last week, completing a thirty-year journey that began at Delhi’s All India Institute of Medical Sciences (AIIMS) in 1985.

On 26 March, the government introduced the rotavirus vaccine Rotavac, indigenously developed under the government’s Universal Immunization Programme. Marketed by Bharat Biotech and approved by the World Health Organisation (WHO), the vaccine comes for 54 per dose, or 162 for three doses per child.

The other two WHO approved vaccines in India, marketed by GlaxoSmithKline and Merck, cost around 2,500 for three doses.

Rotavirus is the primary cause of diarrhoea in children in India and kills as many as 78,000 children under five years of age every year, according to the ministry of health and family welfare. After completion of phase-III clinical trials, the vaccine was made available for the private sector in March 2015.

Work on the vaccine started when an attenuated or weakened strain of rotavirus was isolated from a child at AIIMS in 1985-86. “This strain was found in a lot of newborn babies admitted at AIIMS who were infected with rotavirus but were not getting the disease," said M.K. Bhan, former secretary, Department of Biotechnology. This strain named 116E was isolated and characterised by Bhan, who was then an assistant professor of pediatrics at AIIMS.

Around the same time, Roger Glass, now director, Fogarty International Center, US National Institutes of Health (NIH), was characterising an unusual group of rotaviruses collected from newborns from four continents that also did not cause disease. An exchange of notes between the two scientists led to their collaboration to characterise these rotavirus strains and investigate whether newborns infected with these strains were protected against subsequent severe disease with rotavirus.

Teaming up with NIH, Bhan and his colleagues found that the strain of virus had acquired one bovine rotavirus gene and that made all the difference, making it harmful for bovine animals but not for humans. “We assumed that maybe it genetically transformed by cross transfer of genes between different strains and then lost the ability to cause disease," said Bhan.

The vaccine Rotavac was developed by a joint vaccine development initiative supported by the Department of Biotechnology, Government of India, the Bill & Melinda Gates Foundation, the Research Council of Norway, and the UK Department for International Development. Bharat Biotech invested significantly towards vaccine development along with NIH and other international institutions. And so, Rotavac was developed, a live attenuated monovalent liquid frozen vaccine containing live rotavirus strain prepared in Vero cells.

In 2013, the government announced positive results from a Phase III clinical trial of a rotavirus vaccine developed and manufactured in India. The randomized, double-blind, placebo-controlled Phase III clinical trial enrolled 6,799 infants in India (aged six to seven weeks at the time of enrolment) at three sites—the Centre for Health Research and Development, Society for Applied Studies (SAS) in New Delhi; Shirdi Sai Baba Rural Hospital, KEM Hospital Research Centre in Vadu, Pune; and Christian Medical College in Vellore.

Concerns on efficacy

“The efficacy rate of the vaccine is around 58%. It also has herd immunity that adds to the value which is also important. With this vaccine, you see a dramatic decline in countries where they have been tried," said Bhan. “Rotavirus is responsible for 40% diarrhoea admissions in India, so if this vaccine can eliminate those admissions, it would be a major impact," he added.

Efficacy is also impacted by biological differences among children in different regions of the world.

“Most vaccines don’t work well in developing countries because of the gut problem, especially in developing countries such as India and Bangladesh," said Bhan.

Soumya Swaminathan, director general of Indian Council of Medical Research, said that efforts are on by ICMR and other Indian companies to develop rotavirus vaccine with efficacy up to 80%.