‘Wrong way’: Omicron variant could bring second largest US Covid wave | Omicron variant


tThe BA.5 version of Covid-19 has become the majority strain of the virus in America in a matter of weeks, in a troubling development set amid what may already be America’s second-largest wave of the pandemic. .

It also comes at a time when much of the US has eased nearly all Covid restrictions in public and life has largely returned to normal.

“Covid-19 is clearly not over yet. We are seeing dramatic increases in cases and hospitalizations in many places in the United States,” said Jason Salemi, an associate professor of epidemiology in the College of Public Health at the University of South Florida.

As BA.5, one of its Omicron sub-variants, begins to beat the US, “we’re going in the wrong direction,” Salemi said. “We’ve seen it coming for a while… We’ve seen it go pretty unabated.”

More than one in three Americans live in a county with an average risk of Covid, and one in five are at high risk, according to the U.S. Centers for Disease Control and Prevention (CDC). That’s the highest percentage of the country facing risk since February, Salemi said.

More than 100,000 new cases of Covid are now confirmed in the US every day – a percentage that has remained fairly stable for the past six weeks. While cases have declined in the northeast, spikes are now hitting other parts of the country.

At the same time, hospital admissions have steadily increased since the lowest pandemic dip in April, although the rise was not as sharp or the peak was not as high as the previous waves.

“The older you are, the more likely you are to be hospitalized,” Salemi said. “But the number of hospital admissions is increasing for every age group.”

Hospital admissions tend to lag the cases by several days. But a seemingly stable number of cases with increasing hospitalization means something else appears to be at play, experts said — likely waning immunity in the face of a more contagious, immune-evasive and pathogenic variant.

The virus is evolving to evade the protection against infection offered by vaccination or recovery from a previous illness with Covid and it also appears to be more transmissible.

The immune-evasive properties of the evolving variants make new waves more likely, said Tulio de Oliveira, director of the Center for Epidemic Response and Innovation at Stellenbosch University and the leader of the Network for Genomic Surveillance in South Africa.

“BA.4 and 5 may be the variants that can most easily break immunity,” he said. They are “really capable of reinfection”.

In South Africa, BA.1 — the first omicron variant — offered very little protection against BA.4 and BA.5 contamination, de Oliveira said. The antibodies generated by an infection with BA.1 do not protect against reinfection after two or three months, according to laboratory studies.

Infection with BA.2 seemed to offer some protection, possibly because that wave was more recent, he said.

But while immunity to infection seems low, previous immunity still holds up well against serious consequences such as hospitalization and death.

People who have been vaccinated and those who were previously infected “will easily get BA.4 and BA.5, but they will develop very little disease,” de Oliveira said.

In a preprint study in hamsters, the new variants appear to be much more virulent and pathogenic than previous omicron variants. But South Africa saw no more seriousness from BA.4 and 5 than during its other ommicrons.

Indeed, the severity of these variants depends on the immunity levels in addition to their intrinsic properties. “Utilities [severity] is not only a property of the variant itself, but also of the variant and the population it encounters,” said de Oliveira.

Even before this wave, an estimated 95% of South Africans were protected from vaccination or previous Covid attacks.

“We believe that this hybrid immunity in South Africa is why our BA.4 and BA.5 wave of very low hospitalizations and deaths has remained,” said de Oliveira.

Even if variants are more pathogenic in the lab, a high level of immunity can help keep serious diseases at bay. That is why it is important to stay up to date with vaccinations.

“The first and second booster are very important,” Salemi said.

Still, only 34% of eligible Americans — those over the age of 5 — have received booster doses as recommended by the CDC. While the first booster shot was better in older Americans, the highest-risk age group, the second booster shot was extremely low.

“There’s a lot of potential for waning immunity and decreasing protection from the vaccine, without those booster doses, to do a little more damage to these new circulating variants with some perhaps more worrisome characteristics,” Salemi said. Waning immunity coupled with a more immune-evasive variant means “you may start to see an uptick in some of these indicators of serious illness.”

Deaths in South Africa also remained largely low as hospitals were not overwhelmed. “When the BA.4 and BA.5 waves started, we had completely empty ICs — so anyone who got sick could get good support,” said de Oliveira.

“That will be key in the US,” he said. “It’s very different when another wave comes and the hospitals are already overwhelmed.” That’s one of the reasons the Delta wave was so deadly, because it lasted a long time and kept hospitals full, he said.

Pockets in the US with poor immunity levels — including those who have not been recently vaccinated or recovered from the virus — could see more serious illness. But places with high vaccination rates and recent increases are likely to fare better when it comes to hospitalization and death, he said.

In South Africa, the wave came quickly and ended quickly – but it had significant economic consequences, with people unable to work due to illness.

To minimize the effects of a wave, including the risk of economic disruption and long-term problems such as prolonged Covid, Americans should “reduce the numbers as soon as possible,” Salemi said.

That includes taking the same measures that have been proven in the past to help contain the virus: vaccines, masks, distance, ventilation, tests.

“Please don’t think of mitigation as all or nothing,” Salemi said. “There are simple steps we can take to dramatically reduce risk — not just for ourselves and our families, but for many of those members in our community who are very vulnerable.”

Because each infection presents new opportunities for the virus to evolve and escape immunity, scientists and officials around the world must continue to monitor it, de Oliveira said.

“This virus has surprised us far too many times.”

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