The latest on the coronavirus pandemic and the Omicron variant

From Jan. 17 to 23, Covid-19 cases increased 5% compared to the week before with over 21 million new cases reported, the World Health Organization said in its Covid-19 Weekly Epidemiological Update published Tuesday. 

“Across the six WHO regions, over 21 million new cases were reported, representing the highest number of weekly cases recorded since the beginning of the pandemic,” the update said. 

The case increases were slower than last week, WHO said, with only half of the six WHO regions reporting an increase of new cases, compared with five of six reporting one the week before. 

The largest increase was in the eastern Mediterranean region, 39%, followed by the South-East Asia region, 36% and the European, 13%. The Western Pacific region reported a similar number of cases to the week before. Decreases were reported in the African region, 31%, and the region of the Americas, 10%. 

The United States reported the highest number of new cases, followed by France, India, Italy and Brazil.

There have been over 346 million confirmed Covid-19 cases globally as of Jan. 23.

The number of deaths reported, nearly 50,000, was similar to the week before. 

Three WHO regions reported increases in the number of deaths, the South-East Asia Region, 44%, the Eastern Mediterranean Region, 15% and the Region of the Americas, 7%. The remaining three regions reported declines in new weekly deaths. 

The United States also reported the highest number of new deaths, followed by the Russian Federation, India, Italy and the United Kingdom. 

As of Jan. 23, the have been over 5.5 million deaths reported across the world. 

Infection with the coronavirus, either before or after vaccination, may enhance immune responses, according to a study published Tuesday in the journal Science Immunology. 

The study, conducted by researchers at the Oregon Health & Science University, analyzed antibody responses in 104 vaccinated health care workers. Of this group, 31 people had a breakthrough infection after vaccination, 31 were infected before vaccination (referred to as hybrid immunity), and 42 had no history of infection. 

The researchers found that both the hybrid and breakthrough groups had significantly higher levels of antibodies against Covid-19 proteins compared with the group with no infections. These antibodies were also more efficient and potent, and they had higher rates of virus neutralization: up to 32 times higher in the hybrid group and up to 17 times higher in the breakthrough group. This pattern was seen against the wild-type virus as well as the Alpha, Beta and Delta variants. 

In the group with no infections, antibody levels declined with age, as previous research has found. However, this effect was not seen in either the hybrid or breakthrough groups. No significant differences were observed between the hybrid-immunity and breakthrough cohorts. 

While previous studies have shown increased immune responses from pre-vaccination infections, the researchers claimed there was a gap of knowledge about responses to breakthrough infections. 

However, they highlight the importance of getting the vaccine, regardless of previous infection status.

Experts also warn against trying to develop or boost coronavirus antibodies by catching Covid-19 on purpose. Even vaccinated people can become severely ill or spread the virus to people around them who might be at higher risk for serious complications.

The new study did not include participants with boosters or third doses of the vaccine, though an early external study may suggest that boosters offer increases in immune protection similar to those seen in the hybrid-immunity and breakthrough groups, according to the authors. 

Dr. Anthony Fauci, President Biden's chief medical adviser, said he will discuss efforts toward a universal coronavirus vaccine at an upcoming White House briefing, according to pre-recorded comments scheduled to air Wednesday at 2 p.m. ET on SiriusXM’s “Doctor Radio Reports” with Dr. Marc Siegel.

“There's a big effort, and I'm gonna be talking about this tomorrow at the White House press conference is the efforts that we're putting in to develop a pan-coronavirus vaccine, which is gonna be multiphasic," he said.

"It's not gonna be trying to get a vaccine against all the coronaviruses all at once, but start with a vaccine that covers all the different variants of SARS CoV2. And then get a pan-sarbecovirus, which includes SARS-CoV-1 and SARS-CoV-2 ... a lot of activity that's going on in that regard,” Fauci said.

The White House Covid-19 Response Team briefing is scheduled for 11 a.m ET.