Focus starting to shift from cases to hospitalisations

LONDON • After more than a year of obsessively tracking Covid-19 case numbers, epidemiologists are starting to shift their focus to other measures as the next stage of the pandemic emerges.

With rich countries vaccinating growing proportions of their vulnerable populations, the link between infections and deaths appears to be diminishing. Now, the focus is on learning to live with the virus - and on the data that matters most to avoid fresh lockdowns.

"It's possible we'll get to a stage of monitoring only hospitalisations," said Dr Jennifer Nuzzo, an epidemiologist at Johns Hopkins University's Coronavirus Resource Centre.

Before vaccinations took off in Britain, the United States and Europe, a spike in cases almost invariably translated into a surge in hospitalisations and deaths. The strain on health systems left leaders little choice but to place curbs on public life, disrupting economies.

Now, scientists and government officials are keen to see if the widening scope of vaccinations will finally break that cycle. Events in Britain are providing the most compelling test case to date.

About 46 per cent of the British population is fully vaccinated, helping reduce daily deaths to the lowest level since last summer. Yet cases of the Delta variant, a more transmissible strain first identified in India, almost doubled in the past week. Hospitalisations also ticked higher, though most of the patients have not been fully vaccinated.

If the virus spreads further among children and non-vaccinated young adults, the true test of the immunisation campaign will be whether hospitalisations and deaths stay low. If they do, Covid-19 would begin to look less like an unmanageable pandemic.

"We are aiming to live with this virus like we do with flu," Health Secretary Matt Hancock said.

Scientists say comparing the prevalence of Covid-19 to the flu, which kills about 650,000 people globally each year, will become an important yardstick.

Covid-19 has killed more than 3.8 million people since the start of last year, but vaccinated countries should eventually be able to treat its periodic resurgences in the same way as they do the flu - and make policy decisions accordingly.

In a sign of pandemic optimism - or fatigue - around two dozen US states have reduced how often they release Covid-19 data. Florida now reports just once a week.

In much of the world, however, health officials are not taking their eyes off case numbers yet. Taiwan reduced new infections almost to zero, but a lack of vaccines means that even small outbreaks must be treated as big threats. After a year of relative calm and daily cases in single digits, daily infections rose as high as 723 last month.

"When we look at Taiwan... it underscores the vulnerability of these (places)," said Dr Nuzzo. "They are not going to be able to relax until they're able to vaccinate more widely."

Still, case numbers remain important. The more the virus circulates, the more likely it could mutate into strains that are more lethal or resistant to existing vaccines. People infected with the Delta variant are more than twice as likely to end up hospitalised than those with the Alpha strain, according to research published in The Lancet.

Getting to zero cases is not realistic any time soon, even in highly vaccinated countries. Most societies have come to accept the reality of mutation with other viruses, like the flu, and incorporating the new strains into vaccines when they crop up. That is likely to be the case with Covid-19.

"We have to live with the fact there will be new variants," said Dr Marc Baguelin, an epidemiologist at Imperial College London. "It's something that's always happening in the background."

BLOOMBERG