A considered, not conditioned, fight | The Financial Express

Clipped from: https://www.financialexpress.com/opinion/a-considered-not-conditioned-fight/2927315/

A wave should no longer be viewed as a surge if the vast majority of the cases are asymptomatic or are mild infections

A considered, not conditioned, fightIn 2020, the novel virus found all persons in all countries immunologically naive. (File)

China’s One Belt One Road infrastructure initiative, for linking countries across the globe, may be lagging.  However, Covid-19, which emerged from Wuhan, has knotted the whole world in a tangled pandemic. After China suddenly abandoned its zero-Covid policy, removed travel restrictions, stopped mass testing, and ceased mandatory institutional isolation of all infected persons, a tsunami of cases has been reported. Since the virus does not obey border controls, the rest of the world is alarmed that the hard-fought success of the past year may go up in an airborne viral cloud.

India is worried about a possible resurgence of the pandemic, which had receded after the Omicron wave early this year. The government has commenced the screening of international travellers, issued mask advisories, urged third vaccine doses to all who haven’t yet accessed them, and introduced a nasal vaccine which promises mucosal immunity. States have been alerted and healthcare facilities are being readied to respond to a potential rebound of cases. Medical supplies and oxygen pipelines are being reviewed to assure uninterrupted availability.

Questions foremost in people’s minds are: how worried should we be about China’s Covid surge; are dangerous new variants already amidst us or will come soon; will India experience a new wave; is a third or fourth dose of vaccine needed; should everyone take it or only those at high risk; is it better to take a different vaccine as a booster than those taken previously; and will this virus haunt us forever?

In 2020, the novel virus found all persons in all countries immunologically naive.  The situation is different now. Initially, anyone who was exposed to a high viral dose was infected. Whether they became seriously ill or not depended on age, coexisting health conditions, and response of their immune systems.  Persons with high levels of natural immunity escaped serious illness. Many were asymptomatic. 

People who survived infections and those who were vaccinated with two doses of an approved vaccine acquired sufficient immunity to avoid life-threatening illness when they encountered the virus again. Acquired immunity did not shield against infection but prevented serious illness.

The virus changed too. As new variants emerged, their transmissibility, immune evasion capacity, and manifest virulence differed from the original virus. The Delta wave was ferocious as the variant rampaged through people who had not been infected before or had been inadequately vaccinated. Omicron emerged when levels of acquired immunity had risen in most populations, except in China, which had adopted an obstinate ‘Zero Covid’ policy. Omicron appears less capable of invading lungs and blood vessels. The picture has shifted to one of mild illness in most of those infected.

So, a ‘wave’ no longer represents a surge of serious cases in places like India, where most persons have acquired immunity conferred by virus or vaccine. Unlike China, where many among the elderly are unvaccinated, most Indian adults have received two doses. Many adults have also received a third dose. Several have acquired hybrid immunity from both infection and vaccine. Even if antibody levels fall, cellular immunity is likely to persist. Immunological memory of the virus would not have been erased and bodily defences would not be as unprepared as they were during the initial waves.

A wave should no longer be viewed as a surge if the vast majority of the cases are asymptomatic or result in mild infections, with low rates of hospitalisation or death. 

It should be labelled a ‘wave’ only when hospitals are flooded with serious cases or deaths mount. Since the virus will not disappear and is adapting to stay alongside us, there will be periodic outbreaks when new variants emerge, acquired immunity levels fade or when cold weather gives fillip to respiratory viruses. Unless the proportion of serious illnesses rises, there is no cause for alarm in India.

Much of the media outcry was about the BF.7 variant of Omicron, an offshoot of BA.5. That variant has been around as a known genetic form for nearly two years, though it was named only in May 2022. A few cases have been documented in India too for some months. This variant has not raised concern in countries other than China, where it has encountered many immunologically naive persons. 

Unlike in 2020, countries are not similar in their vulnerability. India is not at high risk from the ongoing Chinese pandemic upsurge.

That assurance remains as long as Omicron continues to be the globally dominant form of the virus, even if it spins off variants within its family. However, danger can come from a virulent non-Omicron variant emerging from the body of a person with low immunity where multiple mutations can occur during a prolonged infection. 

Genomic surveillance is essential to keep watch on emergence of such variants and global data sharing is imperative to assess the behaviour of all emerging variants health systems need to be on alert but not get locked into a ‘Covid response only’ position.

All eligible persons should get the third dose of an approved vaccine, if they haven’t done so. Since many would have also been infected by the virus in the past two years, with or without symptoms, that would have served as an additional dose in prepping the immune system. So, a fourth dose of the vaccine is optional for most. 

Persons who are immunocompromised or very elderly would likely benefit from a fourth dose if they received the third dose more than six months ago. Since heterologous boosters are more effective and are now being permitted, an approved protein sub-unit vaccine or the nasally administered mucosal vaccine may be chosen by those who received other vaccines earlier.

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