Public health experts in India are of the view that reaching herd immunity is unlikely any time in the near future and believe that the virus will continue to circulate. They believe that hospitalisations and deaths will continue to happen but there will be a significant reduction around six to nine months from now. Herd immunity is said to take place, once a large proportion of a stable population becomes immune to a microbe, either through infection or vaccination.

At that point, others in that community who are not immune will be protected because transmission of the virus is blocked by those who are immune. “That is actually herd protection, not herd immunity. If a non-immune person steps out of that protective cordon and travels to a place where the virus is actively circulating, the person can still get infected. Herd immunity is a population attribute, not an individual attribute,” said K Srinath Reddy, president, Public Health Foundation of India (PHFI).82394065Reddy said that in a highly mobile world where people are moving from place to place, a non-immune person will still be very vulnerable.

Therefore, he recommends that it is better for everyone to be vaccinated. “We are in for a long haul in fighting this virus,” said Giridhara Babu, a senior epidemiologist. In other countries like the UK the pandemic appears to be under some sort of control due to the impact of the lockdown and vaccination. On May 3, 2021, the UK reported 1,649 new positive cases, and only one Covid-19 death.

In France, however, cases remained at around 25,000 per day until mid-April. Germany and Spain had peaks in October and again in early 2021 with an intervening period of low cases. “We need to sustain a battle-ready army of health workforce and resources to fight each wave while preparing for the endemic nature of the disease in the long run. Vaccination is our best weapon out there,” added Babu.

With the variants spreading fast in India and a slow pace of vaccination, herd immunity doesn’t look to be within reach, experts say. “With mutations, changing infectivity, and possibility that immunity may not be as effective as initially believed, chronic simmering infection and small spikes is a real possibility,” said Anoop Misra, chairman, Fortis C-Doc. Reddy said that for Covid-19, we still do not know what the herd immunity threshold is, even in a stable population. We do know that many persons who test positive for antibodies after a natural infection may see those antibodies fade after a few months.

“Vaccines are better at that because of a standardised dose of antigen and the booster effect of the second dose. It was a big mistake to declare that we had acquired herd immunity based on antibody surveys. I have warned against the illusion of herd immunity for over a year,” Reddy added.

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The Economic Times

Checkout this section for curated News, Articles & Videos published worldwide by The Economic Times, an English-language, Indian daily newspaper headquartered in Mumbai, India.

Checkout this section for curated News, Articles & Videos published worldwide by The Economic Times, an English-language, Indian daily newspaper headquartered in Mumbai, India.

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