Subvariants of Omicron BA.4, BA.5 and future variants of the coronavirus

As we head into another summer with COVID-19, the coronavirus variant landscape is changing yet again.

A relatively new omcron sub-variant – BA.2.12.1 – now accounts for the majority of COVID-19 cases in the country. But experts say two more variants, BA.4 and BA.5, are catching on and could very well take over in the coming months.

As of June 18, sub-variant BA.2.12.1 is responsible for approximately 56 percent of all COVID-19 cases in the United States, according to the most recent data from the Centers for Disease Control and Prevention.

Meanwhile, the previously dominant BA.2 now accounts for only 9% of cases. As of early May, BA.2 and BA.2.12.1 were each responsible for about half of coronavirus infections in the United States, data from the CDC show. And as of March, BA.1 (the original omicron strain) was still in the lead.

In some areas of the country, BA.2.12.1 has taken over even more: “I’m in Connecticut, and that’s like 80% of all the sequences we see right now,” Anne Hahn, Ph.D., postdoctoral research fellow at the Yale School of Public Health, told TODAY.

“And that turnover between BA.1, then BA.2 and now BA.2.12.1 was very fast, which is a little unexpected,” said Hahn, whose work is studying the viral evolution of SARS- CoV-2. “We are now at BA.5 and it’s June 2022. The first of this whole family emerged in November 2021. So that’s really worrying.”

The rapid turnover of the variants is thought to be due to mutations in each strain, particularly in the spike protein, which could allow the virus to evade immune protection. In the case of BA.2.12.1, “this is believed to help evade some of the antibodies that have been generated by previous infections or vaccines,” Bill Hanage, Ph.D., associate professor of epidemiology at Harvard TH Chan School of Public Health, told TODAY.

But how much of BA.2.12.1’s success “is due to the fact that instead of being inherently more transmissible is not clear,” said Hanage, who is also co-director of Harvard’s Center for Communicable Disease Dynamics.

BA.2.12.1 does it cause more serious illness? “Parts of the country have had a relatively large increase (in cases) with BA.2.12.1, and that hasn’t translated into extremely high amounts of hospitalizations or deaths,” Hanage said.

But it is difficult to assess the true severity of the disease due to this sub-variant. “The vast majority of the population has been vaccinated or had a previous COVID infection, and that will affect the severity of the disease because there is some underlying immunity,” Dr. Anna Durbin, associate professor at Johns Hopkins University School of Medicine, TODAY said.

“The good news we can draw from this is that we are still seeing the protective effects of the vaccine against the more severe forms of the disease,” said Durbin, whose research focuses on evaluating vaccines for infectious diseases.

On the horizon: BA.4 and BA.5

While BA.2.12.1 is dominant right now in the United States, other emerging omicron sub-variants – called BA.4 and BA.5 – are starting to gain ground. First detected in South Africa, BA.4 now accounts for about 11% of cases in the United States and BA.5 is responsible for nearly 24%, CDC data show.

“They are not taking off at the same speed everywhere,” Hanage said, noting that the two new strains appear to be popping up in Texas and Florida and that BA.5 cases are also increasing in Washington state.

“In general, and it’s unclear if there’s a reason for this, they’re taking off faster in places that haven’t seen much BA.2,” he explained. This could be because BA.2 specifically offers some level of protection against these new variants or because simply having a newer infection – of any variant – would provide some coverage, she said.

Hahn said he expects the new variants to “probably take over towards the end of the summer” and noted that Portugal is seeing a sharp increase fueled by BA.5 cases right now. He is “very worrying because this is one of the most vaccinated populations in the world, especially when it comes to boosters,” he added.

Companies are working on the next generation of COVID-19 boosters, which will target specific omicron-related variants. For example, Moderna plans to release a bivalent vaccine this fall that targets the original coronavirus strain, as well as the omcron variant.

This week, the company shared new clinical trial data in a press release, which stated that the vaccine provides better protection against BA.4 and BA.5 than the original vaccine. The booster was even more effective against the original omicron strain.

What kind of variations can we expect to see in the future?

All the experts agreed that the new variants are practically discounted. And, considering the latest dominant variants have all been in the omicron family, that’s a good bet, but not a guarantee, the next ones will be too.

“You never want to bet on being surprised by this, but there seems to be a change,” Hanage said. And, right now, experts aren’t expecting another drastically new variant to pop out of nowhere and dominate as quickly as omicron did, Hahn said.

Previous variants, including alpha, delta, omicron (BA.1) and BA.2 “began to evolve in the first few months after the virus entered the human population. They are not derived from each other,” he explained. Hanage. “But the things we’re seeing now come from omcron, which is a new thing.”

At the same time, however, it is important to recognize that the omicron subvariants are not identical to each other: “We call it the omicron family, but when we actually look at the genetic distance of these family members, they are just as different from each other. alpha was at delta, for example, “Hahn said.

Eventually, the variants “will keep coming; they won’t stop,” Durbin said. “What do we know from other seasonal coronaviruses? They keep coming back, they keep mutating and we keep getting infected.”

The key points that scientists will be looking for are whether the virus starts causing more serious disease, whether we will have to continue receiving boosters to protect ourselves, and whether those vaccines will need to be updated regularly to better adapt to the strains that are circulating, she said. Moderna and Pfizer are both working on booster shots, expected in the fall, that target the omicron variant.

How to protect yourself and your community

We may never be able to completely eliminate all coronavirus variants, Hanage said. But there are things we can do to reduce the chances that more will emerge and reduce the opportunities they have to take over.

  • Continue to wear a mask. Yes, face masks still work, especially the higher quality ones, like the KN95, KF94 and N95 respirators. Wearing masks is especially useful in high-risk situations, such as crowded indoor events. “If it’s a good mask, it will protect you no matter what the people around you are doing,” Hanage said.
  • If you are eligible, make a plan to get your second booster. While Durbin noted that protection from boosters appears to last less and less time – “We’re looking at one to two months,” he said – if you’re over 65 or have underlying conditions that make you more likely to develop severe COVID. 19, the second booster is worth taking. But it’s also worth planning when you’re most likely to want that extra protection, like before your trip or event.
  • Check the data of the Local Health Authority. As COVID-19 is spreading differently in different areas of the country, it’s helpful to keep an eye on the situation near you. There are a few on the CDC’s website, Durbin said, but it usually directs people to the local health department’s website for up-to-date information about their community.
  • If you are sick and can stay home, you should. Even if you’ve tested negative with a COVID-19 rapid test at home, don’t assume you’re safe. “If you can take a sick day, you shouldn’t go to the office where you sneeze, cough and get feverish,” Durbin said. Avoiding the spread of the virus to others and “reducing the overall workload is our best bet against the emergence of new variants,” agreed Hahn.
  • Getting children vaccinated will help protect them and further reduce the population susceptible to infections, Durbin said. This can affect the transmission, as well as the emergence of new variants.
  • I look forward to the next generation boosters. The next crop of vaccines, designed to target specific variants or multiple variants, will be a critical step forward, the experts said. “The current vaccines are designed against a strain of two years or more,” Durbin said. “We know the virus has mutated extensively.”


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