A Covid-19 vaccine developed by India's Bharat Biotech is safe and has shown high levels of antibody response in a mid-stage trial, but follow-on studies are needed to evaluate the shot for children and older people, a peer-reviewed study showed.
The vaccine, India's first successful home-made shot against Covid-19, has attracted interest from more than 40 countries. The company said last week it had shown 81% efficacy in preventing symptomatic Covid-19, based on interim analysis of late stage trials.
The double-dose vaccine showed significantly higher neutralizing antibody responses in Phase II than in Phase I due to the difference in dosing regimens that changed to a 4-week apart injection schedule from a 2-week course, researchers said in the study published in medical journal Lancet on Monday.
But it said the Phase II trial, which had 380 participants, enrolled a small number of participants aged 12–18 years and 55–65 years and follow-on studies are required to establish immunogenicity in children and in older people.
It also said that while the trial included participants from across nine Indian states, the study population lacked ethnic and gender diversity, "underscoring the importance of evaluating BBV152 (the vaccine) in other populations".
Female participants, for example, accounted for just one quarter of the study subjects.
Its Phase III study, Bharat Biotech said last week, has 25,800 participants aged 18-98 and include more than 2,400 people over the age of 60.
The peer-reviwed study is another positive for Bharat Biotech, which had drawn criticism in January after the Indian government approved the vaccine, called COVAXIN, for emergency use without any efficacy data.
Less than 9% of the more than 18.2 million Indians vaccinated so far against Covid-19 had taken COVAXIN as of Tuesday, government data showed.
Many politicians in India, including Prime Minister Narendra Modi, have chosen to be inoculated with the homegrown shot instead of a rival one developed by AstraZeneca Plc and Oxford University.
India, the world's biggest vaccine maker, aims to inoculate 300 million of its 1.35 billion people by August. It has reported 11.24 million Covid-19 infections, the highest number in the world after the United States, with 157,930 deaths.