The second wave of the COVID-19 is taking the edge off though the pace of vaccination has slowed down as well, as the country is facing a shortage of Covid shots. Covid-19 is known to have an inflammatory impact on the respiratory system. Health experts advise keeping blood sugar levels as well as the oxygen level in check. India has so far inoculated 43 per cent of its 60-plus people with one dose (the rates being as low as 35 per cent in Punjab, 39 in Telangana, and as high as 78 in Himachal Pradesh and 80 in Tripura). In the 45-plus group, 37 per cent people have received at least one dose.
Banaras Hindu University researchers have claimed a single dose of vaccine is enough for Covid recovered patients. “We studied the effect of vaccine on Covid recovered and non-infected people. Antibodies in recovered people developed in first week,” Prof Zoology Dept BHU Gyaneshwer Chaubey said.
Meanwhile, Dr N K Arora, chairman of Covid-19 working group under National Technical Advisory Group on Immunisation (NTAGI) said, “India may soon start in few weeks testing feasibility of a regimen that mixes two different doses of Covid vaccines to see if it helps boost immune response to virus.”
Though, the vaccines based on single-dose regimen could allow India to expand its immunisation programme coverage in a shorter period of time. Due to the shortage of doses, the vaccination drive for the 18-44 age groups have been restricted, as several state governments are prioritising the second doses for the 45-plus age group. As per a study conducted, those inoculated with Covishield produced antibodies compared to those who received Covaxin, even though both shots elicited a good immune response. “Among 515 healthcare workers (305 male, 210 female), 95 per cent showed seropositivity (higher antibodies) after two doses of both vaccines. Of the 425 Covishield and 90 Covaxin recipients, 98.1 per cent and 80 per cent, respectively, showed seropositivity. However, both seropositivity rate and average rise in anti-spike antibody was significantly higher in Covishield versus Covaxin recipients,” the study authors show. “Both the vaccine recipients had similar solicited mild to moderate adverse events and none had severe or unsolicited side-effects. In conclusion, both vaccines elicited good immune response after two doses, although seropositivity rates and median anti-spike antibody titre was significantly higher in Covishield compared to Covaxin arm,” researcher AK Singh says.
According to a report by CNN News 18, the Indian government’s study on Covishield would explore the possibility of a booster dose – that could be administered among the beneficiaries after six or 12 months of their first dose. Vaccines such as Johnson and Johnson as well as the Sputnik that use the same viral vector technology for vaccine-making as Astrazeneca are single dose. So, the government believes that the Oxford-AstraZeneca vaccine could also be equally effective with only one dose. However, a study carried out in the UK by scientists at Public Health England found that a single dose of Covishield was only 33% effective against the B.1.617.2 variant that is rampant in India. At two doses, the vaccine was doubly effective as it showed 60% efficacy against this variant.
British-Swedish vaccine make AstraZeneca, whose jab locally produced in India is known as Covishield, had claimed in February that the vaccine is safe and effective at preventing COVID-19, with no severe cases and no hospitalisations, “more than 22 days after the first dose”.
The conclusion was drawn after a primary analysis of Phase III clinical trials, AstraZeneca had claimed. “Results demonstrated vaccine efficacy of 76% (CI: 59% to 86%) after a first dose, with protection maintained to the second dose,” it added.
Dr. Sharvan Sehrawat, immunologist, Indian Institute of Scientific Education and Research (IISER), Mohali to understand the relevance of using a one-shot vaccine in India. “One dose is going to give some kind of immunity. Even the UK tried to prioritise vaccinating its whole population by giving everyone a single dose first, and it worked. We do not have enough data, but it is quite possible that the same regime might work in India,” Sehrawat opined. Dr. N K Ganguly, former director-general, Indian Council of Medical Research and Dr. Sankaran Krishnaswamy, co-founder of Indian Scientists Response to COVID-19, and retired Professor of Bioinformatics, Madurai Kamraj University agreed that there is not enough data but both believed that following a two-dose regime will produce better outcomes.
