Will Covid-19 vaccines protect against emerging variants? Expert answers
Premium- Protection against severe infection seems to have remained high, and probably contributed to the perceived mild disease caused by Omicron
The 54 mutations in Omicron’s genome — and particularly the 34 clustered in a key viral protein called spike — severely weakens the ability of coronavirus vaccines to prevent SARS-CoV-2 infection, according to a report.
However, protection against severe infection seems to have remained high, and probably contributed to the perceived mild disease caused by Omicron.
That bodes well for the resilience of vaccine-mediated immunity against future variants of concern, notes immunologist Wendy Burgers at the University of Cape Town in South Africa said.
Although Omicron’s spike mutations seem to weaken antibody defences, scientists have detected only slight declines in the ability of immune cells called T cells to recognize the virus.
The report further said that these cells are thought to be particularly important in limiting the scope of a viral infection, killing off infected cells and limiting the virus’s spread.
“I really breathed a sigh of relief after Omicron," Burgers says. “I’m optimistic that the T-cell response will be quite resilient even if a new variant emerges."
However, Burgers noted that as antibodies become less relevant for SARS-CoV-2 immunity, T cells become more important, and a viral variant that can evade T-cell surveillance will have a key survival advantage.
“The T-cell response is doing much more of the heavy lifting," she says. “So one thing we might start seeing is T-cell escape," she added.
In general, this accumulation of exposures to SARS-CoV-2 variants should boost immunity, infectious-disease specialist Santiago Ávila Ríos at Mexico’s National Institute of Respiratory Diseases in Mexico City has said.
Ríos and his team reported that multiple exposures to SARS-CoV-2, either through vaccination or infection, amplified antibody responses, as well as responses by immune cells called B cells2.
“Thus, as more persons become exposed to the virus through different mechanisms, the emergence of new variants of concern may impose a lower disease burden," he added.
Meanwhile, the cumulative COVID-19 vaccine doses administered in India crossed 178.26 crore on Thursday.
More than 21 lakh (21,99,122) vaccine doses have been administered till 7 pm.
The ministry said that so far, over 2.03 crore (2,03,60,743) precaution doses have been administered to healthcare workers, frontline workers and those aged 60 and above with comorbidities.
The daily vaccination tally is expected to increase with the compilation of the final reports for the day by late night, it said.
The countrywide vaccination drive was rolled out on January 16 with healthcare workers (HCWs) getting inoculated in the first phase. The vaccination of frontline workers (FLWs) started from February 2.
The next phase of COVID-19 vaccination commenced from March 1 for people over 60 years of age and those aged 45 and above with specified co-morbid conditions.
The country launched vaccination for all people aged more than 45 years from April 1.The government then decided to expand its vaccination drive by allowing everyone above 18 to be vaccinated from May 1.
The next phase of COVID-19 vaccination has commenced from January 3 for adolescents in the age group of 15-18 years.
India began administering precaution dose of COVID-19 vaccine to HCWs, FLWs, including personnel deployed for election duty, and those aged 60 and above with comorbidities from January 10, amid the country witnessing a spike in coronavirus infections fuelled by Omicron variant of the virus.
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