Belief in ‘herd immunity’ was biggest illusion, paved way for 2nd Covid wave, experts say

Experts say the biggest mistake was allowing the virus to travel freely into the rural areas, adding that eradication of the virus now is too far-fetched an idea.

Representational image | PTI

Hyderabad: The belief that a majority of Indians had achieved “herd immunity” against Covid was one of the country’s biggest illusions that paved the way for the massive second wave in April-May this year, according to experts.

Herd immunity refers to the idea that a majority of population becomes protected against a virus either by exposure to natural virus or by vaccination.

The comments were made Thursday at a session the CSIR-Centre for Cellular and Molecular Biology held on “lessons learnt and unlearnt” during the pandemic, and how India as a country handled the pandemic. A number of senior scientists participated in the discussion.

They pointed out that the country’s way of managing the pandemic moved from lockdown to laxity, giving the virus a free rein with new variants. When the pandemic hit and caseload was limited, India acted swiftly by ensuring travel restrictions, prolonged lockdown and ensured transmission was less. But the same wasn’t maintained.

The biggest mistake was allowing the virus to travel freely into the rural areas, which could have been protected, they said.

Eradication of the virus now is too far-fetched an idea, they added.

‘Herd immunity biggest illusion’

One of the panelists, K. Srinath Reddy, president, Public Health Foundation of India, said: “Our big illusion was believing that we had ‘herd immunity’. By the time we came up to early January (2021) we believed that we had acquired the ‘Nirvana of herd immunity’, we had all kinds of experts telling us herd immunity had arrived — politicians and industrialists believed them and of course people wanted to believe them because they wanted to return to normal…

“We had all kinds of public models saying there would be no second wave and that led to complete swing of pendulum from lockdown to laxity and that gave the virus a free rein.”

Reddy pointed out that allowing viruses to travel to rural areas, which otherwise had very low transmission rates in 2020, could have been avoided. A number of elections, from state to local body elections, and religious gatherings paved way for this, and a penalty was paid in the second wave, he said.

Stressing how ‘herd immunity’ spread as a misconception in India due to lack of clarity by public health administrations, Reddy pointed out how people started believing that they would not be infected because they had acquired herd immunity.

“Even the Delhi government had made such statements. Herd immunity is not a magic clock that you can carry from one herd to another. When people mingle with different spaces and crowds, the chances of getting infected automatically becomes higher,” Reddy said.

Reddy noted that with the entrance of new variants, the threshold for herd immunity was revised to as high as 90 per cent. This means that 90 per cent people need to become immune to the virus for herd immunity now.

He also said that seropositivity does not necessarily mean ‘long lasting’ immunity, adding the latest government sero survey does not mean 67 per cent of the population is immune, especially when the case is such that antibodies disappear in 3-6 weeks and state of cellular immunity is unknown.

The survey does not conduct tests to check the capacity of neutralising antibodies, Reddy added.

In July, the Indian Council of Medical Research (ICMR) conducted the fourth round of sero survey to reveal that 67.6 per cent people across the country had developed antibodies against SARS-CoV-2.

Eradication not an option, vaccination needs to be doubled

According to the experts, while vaccination could prevent the severity of the disease and reduce the deaths, which shot up especially during the second wave, eradication of the virus seems impossible with the rate of spread and mutation into new variants.

“For eradicating the virus, vaccination is not the only way out but one of the most important one… The disease should also not have any animal reservoirs. For instance, smallpox could be eradicated because they did not have any animal reservoirs,” said Shahid Jameel, Director, Trivedi School of Biosciences, Ashoka University, Haryana.

Stressing the efficacy of current vaccines and how vaccination could be the only way out, Jameel said India needs to at least double its daily vaccination capacity.

On an average about 3.5-4 million people are being vaccinated in the country on a daily basis. This figure needs to be raised immediately to 8.5 million in the coming days in order to vaccinate the entire population while keeping the spread under control, said Jameel.

Rakesh Mishra, Director of Bengaluru-based Tata Institute of Genetics and Society, pointed out that the Delta variant was the most dominant in the country with “over 97 per cent cases, easily”.

‘Under-counting’ gave false confidence, say experts

Jacob John of Christian Medical College, Vellore, who is also a former ICMR chief, said the government must record the exact cause of death as well as long Covid deaths. This would help give a true picture of the impact the pandemic had on the population.

The cause of deaths should also be linked to civil registrations, he said.

“Undercounting of deaths, cases just gave confidence to people that the epidemic was under control,” he said.

Need strong public health system

The experts stressed the need to revamp the neglected public health system in the country, adding that there needs to be a decentralised decision-making system at block-level, district-level etc.

Reddy said the country has been focusing on advanced care — hospitals, ventilators and oxygen systems, but it needs to strengthen the primary healthcare system and connect it better to territory healthcare.

“Without a strong public health system, we will be tottering on weak legs if we only focus on advanced care and ventilators,” he said.

(Edited by Amit Upadhyaya)