The Omicron BA.2 subvariant will soon dominate in the US, but Fauci doesn’t expect another surge

Dr Anthony Fauci talks about the Omicron coronavirus variant during a press conference at the White House in Washington, December 1, 2021.

Kevin Lamarque | Reuters

According to data released by the Centers for Disease Control and Prevention, Omicron’s more contagious sub, BA.2, has more than doubled its prevalence in the past two weeks and now represents more than 34% of infections. The Covid-19 virus has undergone genetic sequencing. Control and Prevention this week.

BA.2 has steadily grown in proportion to the Covid variants circulating in the US since February 5, when it represented about 1% of genome-sequenced virus samples, according to the CDC. According to Ali Mokdad, an epidemiologist at the Institute for Health Metrics and Evaluation in the US, BA.2 may have accounted for 50% of new infections in the US because many people are performing tests at home without being approved. collected in official data. University of Washington.

Data from Walgreens, which conducted testing in pharmacies nationwide, showed BA.2 to be the predominant variant with 51% of all positive Covid cases in the week ending March 19.

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Although BA.2 is on the rise in the United States, top public health officials don’t expect another dramatic increase in new cases, largely due to the amount of population immunity gained from injections strains and outbreaks during winter omicrons.

“The bottom line is we’re likely to see an increase in cases, as we’ve seen in European countries, particularly the UK,” said Chief White House medical adviser Dr Anthony. Fauci told ABC “This week”. “Hopefully we won’t see a surge – I don’t think we will.”

In the UK, the number of people testing positive for Covid has increased by 16% in the past week, according to government data. Hospital admissions with the virus also increased by about 20%. BA.2 now represents around 44% of all positive cases in London as of March 10, according to the UK Health Security Agency.

Shoppers walk along Oxford Street in London on December 21, 2021.

Tolga Akmen | AFP | beautiful pictures

However, Mokdad said the situation in the US is different from European countries, because the number of omicron infections here is more than during winter. European countries have also dramatically changed their behavior in recent weeks by lifting restrictive public health measures, which has led to a spike in spikes. On the other hand, in many parts of the US, restrictive measures were not implemented during the omicron period, so there is no significant change in behavior to push back new infections, Mokdad said.

In the US, the number of new infections is down 96% from the pandemic record of more than 800,000 on January 15, according to a CNBC analysis of data from Johns Hopkins University. However, the rate of decline has slowed and new infections have essentially stopped at the seven-day average with about 31,000 new infections per day. Hospitalizations of Covid patients are down 90% from the peak of the omicron wave in January, according to the CDC.

Members of the Ohio National Guard assist with testing for coronavirus disease (COVID-19) in Columbus, Ohio, January 5, 2022.

Gaelen Morse | Reuters

While Mokdad expects BA.2 to represent more than 80% of new cases in the coming months, he said the variant’s doubling time has really slowed down recently. The IHME predicts that cases will continue to decline throughout spring and summer, with another surge possible this winter as immunity begins to fundamentally weaken.

“In our view, the pandemic phase of the virus is over,” Mokdad said. “We’re moving into the circulation phase.”

Public health officials in the UK have found that the subvariable is growing 80% faster than the previous version of omicron, BA.1, according to a summary report published earlier this month. Maria Van Kerkhove of the World Health Organization has described BA.2 as the most contagious Covid variant to date and said it is sweeping the world. The secondary variable now represents more than 80% of the worldwide sequenced Covid samples, international database.

Between vaccination and infection, an estimated 95% of the US population 16 years of age and older had developed antibodies against the virus by the end of December 2021 before the omicron wave peaked, according to a CDC survey of blood samples from blood donors. This level of immunity, Mokdad said, puts the US in a good position until winter when the protection starts to lose its effect.

Tatiana Perez, 11, is given a dose of Pfizer-BioNTech coronavirus (COVID-19) vaccine at a vaccination center in San Jose, Costa Rica on January 11, 2022.

Mayela Lopez | Reuters

The antibodies produced by the vaccine decline after about three months, which can lead to a breakthrough infection, although the shots still provide protection from severe illness. Younger, healthier people who have recovered from Covid have immunity for at least 6 months, according to peer-reviewed studies in Denmarkthe UK. and WE. Although these studies were published before omicron, scientists in Qatar recently found that infection 10 months earlier provides about 46% protection against illness from BA.2 in unvaccinated individuals. However, the elderly and those with compromised immune systems are much more susceptible to reinfection.

BA.2 does not make people sicker than BA.1, is less severe than the delta variant, according to a large study in the real world from South Africa’s National Institute of Infectious Diseases. Reinfection with BA.2 – although possible – occurs rarely, According to a February study from the Statens Serum Institute of Denmark in Copenhagen. Public health authorities in the UK have reached similar conclusions about hospitalizations and reinfections. There are no peer-reviewed studies yet.

“The fact that there are similar clinical manifestations of BA.1 to BA.2 gives me some hope that it won’t completely change the game for us in the same way that omicron changed the game. playing from delta,” said Jennifer Nuzzo, an epidemiologist at Johns Hopkins University.

A son and daughter embrace their father, a patient with coronavirus disease (COVID-19) in the Intensive Care Unit (ICU), before an intubation procedure at Providence Mission Hospital in Mission Viejo, California, USA, January 25, 2022.

Shannon Stapleton | Reuters

There was also no significant difference in the duration of protection given by Pfizer and Moderna shots against mild disease due to BA.2 versus BA.1, According to a study published this month by scientists based in Qatar, which is also not peer-reviewed. The vaccine was 50% effective at preventing mild disease from both omicron variants three months after the second dose, but the protective effect was negligible after that time. However, the two-dose vaccine still provides more than 70% protection against hospitalization and death, and booster doses increase this protection by more than 90%.

Fauci said this week that there is no need to re-implement Covid restrictions at this time. The CDC said earlier this month that 98% of people in the US live in areas where they no longer need to wear masks in public indoor places under the new Covid guidelines. Public health authorities in the US have shifted their focus to hospitalizations, rather than just new infections, when assessing the threat the virus poses to the community.

A shopper wears a protective mask as he enters a store as New York State’s indoor mask regulations go into effect amid the coronavirus disease (COVID-19) outbreak in New York City, New York, USA, December 13, 2021.

Mike Segar | Reuters

The Biden administration is relying on a strategy of vaccination, testing, and antiretroviral treatment to prevent the virus from disrupting daily life. About 75% of adults in the US are fully immunized, according to CDC data.

Dr. Paul Offit, an infectious disease specialist at Children’s Hospital of Philadelphia, said the public should focus on hospitalizations, a measure of more severe illness, rather than just infections. new insect. Between vaccination and infection from omicrons, Offit said, there is likely to be enough immunity in the population to protect against the spike in hospitalizations due to BA.2.

“For now, I choose to be optimistic that we will only have a lot of mild illness and not see a sharp increase in hospitalizations,” Offit said.

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