Will 2022 be the year we stop worrying about Covid waves?

Will 2022 be the year we stop worrying about Covid waves?

Immunity from widespread infection and vaccination could mean future outbreaks will resemble those of the flu rather than April’s catastrophic second Covid wave

25.11.2021

Going into its third year, Covid-19 seems to be entering the endemic phase, meaning it will continue to circulate in the population but in a more predictable and less severe way. With time, the disease could even become similar to routine illnesses, such as the flu and common cold, experts say.

But the transition will happen at different times in different places, and the disease’s impact on the population will broadly depend on two factors: vaccination coverage and mutation of the virus.

The first countries to emerge from the pandemic are likely to be those with either high inoculation rates, such as the US and the UK, or widespread immunity among people from exposure to the coronavirus, like India. In that light, India’s high case count could be a silver lining.

In July, Indian Council of Medical Research’s nationwide serological survey showed over 70% of the surveyed population in eight states had been exposed to the virus (Table 1). “We can say we’ve reached the endemic stage not due to vaccination but due to natural infection,” Dr T Jacob John, retired professor and head of the departments of clinical virology and microbiology at CMC, Vellore, told TOI recently. In New Delhi, which was ravaged by the second wave, a serological survey report published by the government last month indicated over 90% of the population had been exposed to the virus, meaning the city is unlikely to witness a surge in cases unless a new variant emerges. The survey further showed vaccination provided a strong immune response, irrespective of any previous history of symptomatic infection (Table 2).

Variants and virulence

To measure the transmissibility of a virus, scientists often use R0 (or R naught) to denote the number of people a sick person is likely to infect when a population is vulnerable or without immunity. Flu has an estimated R0 of two (one person is likely to infect two others, on average), which rises to between six and seven for the Covid-19 Delta variant.

The Delta variant has affected countries like Singapore and China, which have high inoculation rates but little natural immunity because of strict lockdown measures. In Russia, which still has low vaccination coverage, the variant has wreaked havoc in recent months.

Epidemiologist Neil Ferguson of Imperial College London recently told Reuters that for the UK, which was also hit by the variant, the “bulk of the pandemic as an emergency is behind us”. But he expects above-average deaths from respiratory diseases due to Covid-19 to continue for the next 2-5 years. “It’s going to be a gradual evolution. We’re going to be dealing with this as a more persistent virus.”

For the US, Trevor Bedford, a computational virologist at Fred Hutchinson Cancer Center who has been tracking the evolution of SARS-COV-2, said he sees a milder winter wave and then a transition to the endemic stage in 2022-2023.

Getting a grip on the virus

“We think between now and the end of 2022, this is the point where we get control over this virus... where we can significantly reduce severe disease and death,” Maria Van Kerkhove, an epidemiologist leading the WHO Covid-19 response, told Reuters earlier this month.

But reaching a goal of zero Covid-19 cases worldwide might be a tough ask in the near future. The virus’s high transmissibility, potential to mutate and associated unpredictability make eradication and management efforts more challenging.

Currently, the best bet is to inoculate as many people as possible and give governments the elbow room to tinker with Covid-19 management strategies in preparation for a long-term endemic phase, experts say. Meanwhile, antiviral pills, which will work together with vaccines, might become critical for treatment, and booster shots targeted at the latest variants could provide additional protection. For the larger population, a behavioural shift is needed where Covid-19 is not seen as a one-time threat but as part of day-today life. It would mean a change in the way we think about building, restructuring and operating in shared spaces.

“We are in the endemic stage for the long haul,” said retired professor John.

Text: Sweta Chatterjee

Sources: ICMR, Co-WIN, WHO, Reuters, media reports