The Covid-19 shadow still looms | Latest News India - Hindustan Times
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The Covid-19 shadow still looms

Dec 31, 2022 12:12 AM IST

With the virus now sparing no one, Long Covid was a serious problem to deal with, which easily was the most important implication of how the pandemic had changed in its third year.

Is the glass half full or half empty?

The Omicron variant was a version of Covid-19 that was so far removed from its predecessors that several assumptions about the virus became redundant in 2022. (AFP/Imaging by Malay Karmakar)
The Omicron variant was a version of Covid-19 that was so far removed from its predecessors that several assumptions about the virus became redundant in 2022. (AFP/Imaging by Malay Karmakar)

This was the question posed in our special feature when we looked ahead to 2022, exactly a year ago. At the end of 2021, the Omicron variant had just arrived, bamboozling scientists with its large constellation of mutations and an unprecedented ability to infect more and more people, but causing far milder disease. Before governments could react, the Omicron variant was ripping through entire cities and states, triggering reinfections and leaving the last of the lucky ones – who never had symptomatic Covid in the first two years – unspared.

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After a debilitating 2021, when the Delta variant caused immense suffering in mostly unvaccinated populations, 2022 became the year that 2020 could have been: people ditched masks, resumed travelling, and even got married in record numbers.

The year, therefore, panned out in the most optimistic of scenarios first thought out – or, the glass-half-full view.

Changing pandemic equation

The Omicron variant was a version of Sars-CoV-2 that was so far removed from its predecessors that several assumptions about the virus became redundant in 2022.

The first of these was how long infected people had to isolate. Many countries shortened the mandatory period for people to stay isolated from 10 days to seven, with some even cutting it down to five. Several researchers found that two negative tests on days 6 and 7 were reliable determinants of whether an infected person was contagious.

A second key change the Omicron variant brought on was the need for new vaccines. It was in January 2022 itself that the first evidence emerged of how it was more resistant not just to antibodies – which latch on to circulating virus and disable them – but also to immune memory. Researchers from La Jolla Institute published in the journal Cell a study that found memory B cells, which churn out antibodies, could recognise only 42% of the heavily mutated virus.

It was borne out in real world data too. The UK Health Security Agency that month said protection from symptomatic infection drops to 18-20% in people who had two doses. Booster doses helped lift this protection to 65-70%, but even that began to fall soon. Vaccine makers Moderna and Pfizer-BioNTech, which used the quickly reconfigurable mRNA platform, had their new, updated doses approved by August in the US and the UK. Third, with the virus now sparing no one, Long Covid was a much more serious problem to deal with, which easily was the most important implication of how the pandemic had changed in its third year.

The unseen damage

That Long Covid was leading to a large impact on the quality of people was little understood until recently. In 2022, a pivotal study emerged from The Netherlands, where researchers carried out what is regarded as the most reliable assessment of Long Covid. They found that one in eight people who had Covid-19 have problems such as breathlessness and general tiredness 90 to 150 days after their infection. The study, published in The Lancet in August, said that researchers found over a fifth of people with Long Covid experienced at least one of the residual symptoms to moderate severity.

But even less understood was the science and physiology behind it. And here too, the year yielded some important insights.

A case of even mild Covid-19, scientists from Stanford and Yale found, could lead to significant effects on the brain, effects that they said was similar to receiving chemotherapy.

The study found there was residual neuro inflammation, and a high level of microglia – a type of immune response in the central nervous system. In other words, there was reason to believe some infection may have remained. Later, in December, a study published in Nature by researchers from Maryland, US, detailed evidence to contend that in some patients, the SARS-CoV-2 can cause systemic infection and persist in the body for months.

Looking to 2023

The year also was a reminder that scientific evidence is supreme. China learnt this lesson the hard way when it continued to persist with its Zero Covid policy of hard lockdowns to stamp infections. It was in March 2020 that epidemiologists (from Imperial College London) said dealing with an infectious disease was possible only when there was adequate immunity, either by exposure or vaccine, and that lockdowns were an option only to slow the spread – not stop it. Today, forced by mass protests by a population that ran out of patience, China has undone the policy, triggering a massive spike in infections that no one truly knows the scale of. What implication this mass spread holds for the world will only become clear over time, especially since the threat of mutations grows in tandem with how widely a pathogen continues to spread.

A second key sign scientists are already looking at is how the Omicron variant is evolving. In the last week, scientists have flagged a variant called XBB1.5, which appears to have originated in the US. This variant is causing a spike in cases in America (though hospitalisations are still under control). But perhaps what is of particular scrutiny is cellular characteristics: the new variant, some have said, possesses “alarming antibody evasion properties”. This is, to be sure, still not as much of a jump as when Omicron first arose, but that a single amino acid switch could perhaps change that is reason enough to remember the world is likely to live under the shadow of a coronavirus threat, unless there is a major breakthrough in vaccines or therapies.

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