Would the strategy to get ‘zero’ covid infection for a safe living be practical? Or living with the virus like the ‘seasonal flu’ be viable? The authorities in countries, such as Australia, New Zealand, South Korea and Singapore, aspire for zero virus approach, while Israel, UK, US and European countries have ventured into trying an alternate option, called, ‘soft suppression [1]’.
What is soft suppression? Adjust its safe management measures in stages, subject to trends in serious cases. This could mean fewer restrictions on social gatherings, larger dine-in groups and lower requirements and higher capacity for events. Vaccinated individuals will be able to engage in a wider range of social activities and in larger groups, while unvaccinated individuals may only do so with negative pre-event testing results. Practically all social and workplace restrictions can be lifted, although some critical measures, such as mask-wearing and precautions for large events may remain.
If the incidence of severe illness from COVID-19 remains low despite clusters emerging from time to time, one would eventually be able to arrive at a truly endemic state. This would be the roadmap of transitioning to a “Covid-resilient” society in which the virus is part of daily life.
Israel is the first country to embark publicly on this new strategy, ‘soft suppression’ for life in the era of coronavirus, based on the assumption that the pandemic is here to stay but can be managed with minimal damage to the economy. This involves issuing ‘green pass’ to those vaccinated or with negative RT- PCR for any indoor gathering or immigration into the country! Knowing that the virus has an incubation period of at least a week, is it not a risk to allow passive carriers that could potentially initiate super spreader events? Yes.. but it is a calculated risk! How?
Not that it would be zero cases! But the cases would not raise very much and would be within manageable limits. This is based on the fact that the world is no more the same like the one last year at the peak of the pandemic when the cases rose exponentially sharply. Now there would be many around who had developed immunity due to infection and many more with vaccination! Is it not a safer world now? If a large population have antibodies, the chances of spreading the infection is that much less! This can be achieved either by vaccination or by natural infection. Sero survey is a cost effective method to assess the fraction having antibodies. The assessment is done by identifying presence of covid-19 antibodies in the blood samples. Those who are sero positives, even if they are exposed to infection would not be infected. If a large fraction is a community are sero positives, the infection not only would not spread but ultimately would die out. A quantitative number to achieve this state is not yet available for covid, though it is expected to be higher than 75%.
For example, a sero survey conducted in June in Ahmedabad city municipal corporation (AMC) in India, with a population of 7.5 million, showed 81% sero positivity [2]! Even though, when the survey was done it had hardly vaccinated less than half its population even once. The presence of antibodies in such high fraction could only be explained by massive natural infection in the second wave in late March- April.
It has also been reported that these antibodies detected in sero surveys wane over time but the resistance to the infection is sustained with the cell mediated immunity; studies have shown such protection could even last for one’s life time [3]. Studies indicate that the adeno type vaccines, such as Asteazenica, JJ and Sputnik, would provoke stronger cell mediated responses than the novel mRNA type vaccines!
In the case of AMC, it was found around 30% of those who had past infection did not show antibodies in earlier surveys. Thus the fraction with cell mediated immunity could easily add an additional 10 to 15% to those detected to be having antibodies in the present survey, making the total up to even 95%! It does reflect in the daily number of new cases which has fallen steeply from a peak of 5500 in late April to double digit by June itself and to a single digit soon thereafter! There is no lockdown in this city presently. Not even 60% of the population have received the jab even once as of today! The city has been logging in single digit daily cases for over a month indicating ‘herd immunity’!

In contrast, those states that have lower sero positivities are struggling to bring down the case numbers: for example, in another Indian state, Kerala, only around 45 per cent people have developed antibodies against the national average of 67% in a survey conducted in late June [4]! Only around 40% have received at least one jab in this state till now. Even then, test positivities continue to hover over 10% for over a month even now. Kerala pursued aggressive contact tracing policy through which it could bring down the daily case numbers during the peak of infection but the flattening has been found counterproductive as it has dragged the duration of the menace! A state which was patted for effective management of the infection last year, is paradoxically the only Indian state, that is struggling to bring down the cases!
Obviously the lesson, to those countries trying to drive away the virus by draconian lockouts, is to adopt ‘soft suppression’ and get on to live with the virus! Especially when vaccination is aggressively being pursued and are with over 70% sero positives. Singapore would soon embark on this strategy given its high vax compliance [5].
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