Booster increases antibodies, improves protection: Experts
Scientists urge caution, say boosters are simplest step forward for many
New Delhi, Dec. 12: A booster dose against
Covid-19 raises the amount of circulating antibodies and is shown to increase protection from symptomatic infection with Omicron, scientists have said, underlining that boosters can be the simplest step forward, especially for the immunosuppressed.
Reacting to the statement of UK Health Security Agency (UKHSA) that booster dose of Covishield vaccine is effective against Omicron and a third booster dose of
Covid-19 vaccine provides
70-75 per cent protection against symptomatic infection from the Omicron variant, the virologists and epidemiologists underlined that booster doses of any vaccine (except live attenuated like oral polio vaccine or OPV, measles) exponentially raises antibody level.
Eminent virologist Dr Shahid Jameel said a booster shot after two doses increases the amount of circulating antibodies and is shown to increase protection against symptomatic infection with Omicron.
“We don’t know how well two doses continue to protect against severe disease,” he said.
On what India should do where majority of population is vaccinated with Covishield, the former head of the advisory group to the Indian SARSCOV-2 Genomics Consortia (INASACOG)
said it must be ensured that those who got only one dose of Covishield get the second dose in 8-12 weeks instead of 12-16 weeks.
“Carry out lab studies with Omicron to learn how well sera from Indian vaccines of Covaxin and Covishield neutralise the virus. Make a policy on boosters. What vaccines to use? Who should get it? And when? Make a policy and start vaccinating children starting with adolescents,” he said.
Jameel said in India, four vaccines can be used as boosters: Covaxin in people who got Covishield and vice versa, DNA vaccine ZyCov-D, Covovax protein vaccine from SII
and Corbev ax-E protein vaccine from Biological E.
The health ministry told the Lok Sabha last week that the National Expert Group on Vaccine Administration for Covid19 (NEGVAC) and the National Technical Advisory Group on Immunisation (NTAGI) are considering scientific evidence related to justification for booster doses against the Coronavirus.
Noted virologist Dr T. Jacob John said booster doses of any vaccine (except live attenuated like OPV, measles) exponentially raises antibody level: “Pfizer vaccine some
40-fold high”.
“If we are interested in being cautious about the
unknown risks of Omicron, boosters for as many as possible is the simplest step forward, especially for the immunosuppressed, seniors and those with co-morbidities. This is in the best interests of their welfare,” he said.
John, the former director of the ICMR’s Centre of Advanced Research in Virology, stressed that children must be vaccinated too since unvaccinated large segment of population can act as reservoirs — “plus Omicron seems to go after children”.
“Better to prevent than to wait for evidence. Protection delayed can also mean protection denied,” he said. —