This is what we know so far about the rise in COVID cases

Cases of covid are declining in the United States and more and more states are lifting their mask mandates. However, in the first 10 days of March, more than a third of wastewater sampling sites in the country showed increasing levels of COVID-19. So the question arises: will COVID ever disappear?

For experts, there are plenty of reasons to believe that Americans shouldn’t let their guard down just yet. “The world, for whatever reason, decided that the COVID pandemic is over, and that really worries me,” said Akiko Iwasaki, a professor of immunobiology at Yale School of Medicine. “Lifting all these mandates so quickly is asking for trouble.”

What is the status of the situation?

Throughout the pandemic, COVID-19 trends in the United States have largely tracked those in Europe and the United Kingdom by a few weeks. For most of the European region, COVID cases are on the rise again after declining following their omicron winter spikes.

“With the rise in cases abroad, scientific and medical experts have made it clear that, in the coming months, there could also be a rise in cases of COVID-19 here in the United States,” the press secretary of the United States warned on Tuesday. the White House, Jen Psaki, during a briefing.

His comments came just two weeks after the White House lifted his mask mandates.

“What’s happening in Europe could very well be a preview of what’s going to happen in the United States, especially without masks,” Yale’s Iwasaki said.

There are three main factors driving the rise in international infections, all of which could apply to the United States, experts said. The first is omicron’s suspected cousin, called BA.2, which is reportedly more transmissible than its predecessor, according to a preliminary study from Denmark. In Europe, this variant has rapidly overtaken the initial omicron strain, BA.1, and now accounts for the majority of cases in the UK, according to its Office for National Statistics.

This has not yet happened in the United States, although in recent weeks the prevalence of BA.2 has increased. It currently accounts for just under a quarter of cases overall, according to Nowcast data from the Centers for Disease Control and Prevention (CDC).

Andy Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, said it will be important to look at whether the rise in prevalence of one variant corresponds to a rise in cases overall. While the percentage of BA.2 cases in the United States has nearly doubled in the past week, there has yet to be a corresponding rise in COVID infections, he noted.

Declining immunity is a factor driving the rise in infections abroad. Despite high vaccination rates in much of Europe, booster rates still hover around 50%. In the United States, booster rates are even lower, according to the CDC. The protection of the initial series of two-dose vaccines diminishes after six months. In addition, immunity from a previous infection also declines over time, and newer variants can make antibodies from older strains less effective.

What are the experts worried about now?

BA.2 appears to be no more severe than omicron, meaning that for most healthy, vaccinated people, symptoms are fairly mild. British researchers found that BA.2 does not appear to carry a higher risk of hospitalization than the original omicron mutation.

However, concerns lie with the many unknowns with omicron, which is still relatively new. The same UK researchers found cases of reinfection with BA.2 after omicron infection, meaning that people cannot rely on previous immunity to prevent future infections. Studies are underway to better understand why that might be the case with BA.2.

Some epidemiologists have raised concerns that the virus may be evolving to produce more problematic variants. European researchers argue in Nature Reviews Microbiology that omicron demonstrated COVID’s ability to rapidly mutate in a short period of time to better evade a person’s immunity and even genetically diverge between sublineages, as BA.2 does.

What protection measures do we have?

Two years of pandemic life have given us some strategies to soften the blow of the virus.

Ali Mokdad, a professor at the Institute for Health Metrics and Evaluation and director of strategy for population health at the University of Washington, said he doesn’t think it’s necessary to bring back mask mandates in the United States right now, especially with the warmer weather. But in higher-risk settings and for more vulnerable populations, he recommends wearing a mask.

Johns Hopkins’ Pekosz said that should include children under the age of five who have not yet been vaccinated. Children under the age of 17 were hospitalized at an alarming rate during the omicron surge.

“If you’re in one of those groups that are at high risk for severe COVID, it’s perfectly acceptable for you to continue to wear the mask when you’re in or out of group settings,” Pekosz said. “I have always encouraged people that if they are not comfortable without wearing a mask, they should put one on and continue to do so.”

Experts have continued to emphasize that the best protection we have against the virus, and against severe illness and prolonged COVID, are vaccines. Two-dose messenger RNA vaccines and boosters, such as those made by Pfizer BioNTech and Moderna Inc., reduce the risk of serious illness. But most people need a booster, which is essential to boost immunity against newer variants.