Surge in BA.5 cases shows need for vaccine against all variants, experts say

Repeated surges in COVID-19 cases, the latest of which is mostly from the BA.5 omicron subvariant, likely will continue until a new vaccine is developed that can more effectively fight off all coronavirus variants, medical experts said.

BA.5 has quickly become the dominant version of COVID-19, representing 65% of cases nationwide for the week ending July 9, according to Centers for Disease Control and Prevention data. It is one of several subvariants of omicron that have emerged in succession in recent months, and is the most contagious one yet.

The emergence of BA.5 only a few weeks after a previous spike in cases caused by other omicron subvariants — and a few months after an even larger surge that began with the original omicron strain — isn’t surprising, experts say. Many people were infected during the omicron era, and fewer have been wearing masks and taking other precautions.

Those factors facilitated the further spread of the coronavirus. That, in turn, opened up more possibilities for changes in the virus that led to more infectious subvariants, scientists and doctors said.

“We have a very substantial challenge ahead, as we try to minimize the ongoing impact of this virus and its variants into the future, because it’s not going to just disappear,” said Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases and a professor at the Vanderbilt University School of Medicine in Nashville.

BA.5 is not only very different from the early versions of the coronavirus. It also is different enough from previous omicron subvariants, such as BA.2, BA.2.12 and BA.2.12.1, which had been dominant since March, that someone infected a few weeks ago could get reinfected with BA.5.

“You can think of the variants as, if you will, sons and daughters of the original omicron,” Schaffner said. “And if they are sufficiently different from their parents’ strain, our immune systems are only partially successful in preventing infection and illness. And if they are sufficiently different, and the virus is very contagious — and now we’re describing BA.5 — you can get reinfected.”

The vaccines against COVID-19, including booster shots, help reduce the chance of reinfection, he said.

Federal health officials said Tuesday that vaccines targeted more specifically at BA.5 and BA.4, currently the second-most-common subvariant, may be ready as early as October. They would be more effective than the current vaccine even if another omicron subvariant becomes dominant, said Neville Sanjana, an assistant professor of biology at NYU and a core faculty member at the New York Genome Center.

But, Sanjana said, the “game-changer” would be a “pan-coronavirus vaccine,” which scientists are trying to develop to combat future variants, including ones very different from omicron. Ideally, it would be delivered through the nose, because if the vaccine can attack the virus where it often enters the body, it can prevent it from spreading further, he said.

Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Medicine, said a pan-coronavirus vaccine would attack parts of the virus that are the same for all variants. The current vaccine has become less effective because it attacks the tips of the virus that attach to human cells, and they have mutated over time, she said. The top parts of BA.5 are significantly different from those of the original coronavirus, she said.

BA.5 helped push Long Island’s seven-day average of positive test results to 10.9% on Monday, after numbers had started to decline following the last surge in May. It has since fallen to 10.3%.

The late springs and summers of 2020 and 2021 had low rates of COVID-19, with positivity rates well under 1% from mid-May to early July 2021. The delta variant caused numbers to rise in mid-July 2021, but not nearly as high as this summer.

The higher rates now are in part due to how contagious BA.5 is, Schaffner said. But, he said, “The second thing is our behaviors. I think there are fewer people wearing masks, and more people going to congregate settings this summer than they had in the previous summers.”

As in past summers, people are socializing outdoors, where transmission of the virus is much lower than indoors, he said. But, he said, with a virus as contagious as BA.5, crowded outdoor activities are riskier than in the past. In addition, he said, “We’re spending a lot of time indoors in air-conditioned spots. We’re going back to business. We’re going to concerts, we’re going to restaurants, the movies, houses of worship.”

The virus itself is much different physically than in the past, said Dr. Dwayne Breining, executive director of Northwell Health Labs.

Viruses are constantly reproducing in human bodies to infect cells, and as they’re doing so, the copies aren’t always exact, he said.

“99.9999% of those mutations are incompatible with life for the virus, so you never hear about them,” Breining said.

Of the tiny number that transmit from one person to another, only a small number spread to multiple people, he said.

For those that end up dominating, “What you’re essentially seeing is a rapidly accelerated example of Darwinian evolution, where it’s natural selection,” Breining said, referring to how organisms better able to adapt to their environment are more likely to survive.

That’s why variants and subvariants have become significantly more infectious as the pandemic has continued, he said. The variants with mutations that make it easier to infect cells spread more widely and survive, he said.

The first variant, called D614G, became dominant by July 2020, said Sanjana, co-author of a study on D614G.

The D614G mutation, which became part of the omicron and other variants as the virus evolved, was minor enough that it alone had little effect on immunity from the vaccine and prior infection, Sanjana said. The spike protein of the coronavirus — which is what latches on to cells to infect them — was “almost the same,” he said. The antibodies produced by the vaccine “are geared toward a very specific version of spike and can tolerate some differences,” he said.

But BA.5 has numerous mutations in the spike protein, Breining said. He compared antibodies produced by the vaccine and previous infection to puzzle pieces that are “designed to fit a very specific matching puzzle,” which in the case of the coronavirus is the spike protein that protrudes like spikes from a crown. They recognize those spike proteins and attack them. The antibodies are less effective with BA.5 because BA.5 is so different, although they still help reduce the chance of infection, and the vaccine remains effective at preventing severe disease and death, Breining said.

The names of the variants indicate how distinct they are from one another, he said. BA.5 is more different from BA.2 than BA.2 is from BA.2.12, and even more different from delta.

Omicron has led to fewer hospitalizations per new case than previous variants. The vaccine, and the large number of people with previous infections, are key reasons, Nachman said. It also may be a milder disease, she said.

Despite that, and despite how doctors are better able to combat COVID-19 than earlier in the pandemic, the disease remains lethal for some, especially for many unvaccinated people, who have a far higher death and severe-disease rate than vaccinated people, Nachman said.

An average of more than 300 people a day nationwide are still dying from the disease, CDC data shows.

“This still can be an overwhelming infection,” Nachman said. “And it can cause horrible disease of the lungs and heart and kidney and lead to death.”