Just a week after private laboratories in Mumbai started offering the ‘Spike protein antibody’ test – which detects proteins created by immune system to fight the SARS-CoV-2 virus — a large number of vaccinated healthcare workers are getting themselves checked to understand if the Covid-19 vaccine is effective in their bodies.
According to a Times of India report, some healthcare workers are using the test to time the second dose of vaccination even as debate continues on the time interval between the vaccine doses, with the World Health Organisation saying the second dose is most beneficial if taken between 8 to 12 weeks. India has stuck to the minimum four-week gap between two doses.
“The test will give us a lot of data on low, moderate and high antibody levels which can throw light on how much is adequate to fight the virus,” Dr Nilesh Shah, Metropolis Healthcare president, was quoted in the report as saying.
According to researchers, the neutralising antibodies induced by some of the vaccines being used in the US, such as the Pfizer and Moderna are reportedly significantly less effective against the SARS-CoV-2 variants first described in Brazil/Japan and South Africa.
Neutralising antibodies work by binding tightly to the virus and blocking it from entering cells, thus preventing infection, the study says. Like a key in a lock, this binding only happens when the antibody’s shape and the virus’s shape are perfectly matched to each other.
If the shape of the virus changes where the antibody attaches to it — in this case, in SARS-CoV-2’s spike protein — then the antibody may no longer be able to recognize and neutralize the virus as well. The virus would then be described as resistant to neutralization, the researchers said.
Currently, all approved Covid-19 vaccines work by teaching the body to produce an immune response, including antibodies, against the SARS-CoV-2 spike protein. While the ability of these variants to resist neutralizing antibodies is concerning, it doesn’t mean the vaccines won’t be effective.