Covid antibodies may not help build long-term immunity against virus, finds study

New Delhi: Amid speculation that coronavirus antibodies, once developed, will help fight reinfection or boost immunity against the deadly virus, a study indicates that this may not necessarily be possible for everyone. A new study has found that post-Covid-19 infection, antibody response actually scales down instead of building immunity over time. This was witnessed more among the elderly group than other groups.

The researchers at Imperial College in London tested more than 365,000 people between June 20 and September 28. They found that just 3 months after the first round of tests, there was a fall in antibodies by 26 per cent -- which was greater among those above the age of 65 as compared to the younger population. Author of the study, Prof Paul Elliott said, "Our study shows that over time, there is a reduction in the proportion of people testing positive for antibodies. It remains unclear what level of immunity antibodies provide, or for how long this immunity lasts."

Antibody provides great protection to the body, but T cells contribute to the immunity too. Thus, one might reserve their judgement on the direct correlation between the fall of antibody and immunity. However, the research dashes hope of herd immunity being a possible answer to the lockdown, especially when it`s quite clear now to all that the Covid-19 virus is here for a long haul.

IS CORONAVIRUS REINFECTION POSSIBLE?

Professor Helen Ward, one of the lead authors of the report said, "This study has shown that the proportion of people with detectable antibodies is falling over time. We don`t yet know whether this will leave these people at risk of reinfection with the virus that causes Covid-19, but it is essential that everyone continues to follow guidance to reduce the risk to themselves and others." "When you think 95 people out of 100 are still likely to be susceptible, we are a long, long way from anything resembling population-level protection against onward transmission. It`s not something you can use as a strategy for infection control," she further said.

Like the common cold virus, antibodies of coronavirus post-infection peak for three to four weeks and then fall in numbers, thus escalating the chances of re-infection though there have been only a few documented cases of re-infections. Researchers warn that not enough time has passed since the infections peaked in March and April. Researchers have also found out that young people from the black and Asian minority communities (BAME) and health workers had higher antibodies possibly because of closer contact with infected individuals.

URGENT NEED OF COVID VACCINE

The need for a vaccine becomes all the more urgent in such a situation even as this research has raised questions on the effectiveness of the antibodies generated by the vaccine. Refraining to conclude the vaccine at this stage, Professor Paul Elliott, director of the REACT-2 study, said, "The vaccine response may behave differently to the response to natural infection." At the same time, he did not deny the need for a booster dose of the vaccine in some people. Reacting to The Sun newspaper`s report stating the vaccine might be rolled out from November 2 this year, Health Secretary Matt Hancock said, "On my central expectation, I would expect the bulk of the rollout to be in the first half of next year."