BA.5, a new Omicron subvariant of the coronavirus, has become dominant in the U.S., accounting for 65% of infections nationwide, according to the Centers for Disease Control and Prevention. Some experts have called it “the worst variant we have seen so far,” due to its high transmissibility and its ability to evade immunity conferred by vaccination or prior infection.
“People with prior infection, even with BA.1 or BA.2, are likely still at risk for BA.4 and BA.5,” Rochelle Walensky, director of the CDC, said on Tuesday at a virtual press briefing by the White House COVID-19 response team.
Walensky and other top U.S. health officials, including Dr. Anthony Fauci, warned that a new surge driven by the Omicron subvariant is here. However, they said that so far, BA.5 has not shown signs of causing more severe disease.
“We know now, from experience that we’ve had over the last couple of months and others in other countries, that it doesn’t appear to be associated with greater disease severity or hospitalizations compared to the most recent subvariants,” Fauci said.
The White House COVID-19 response team also emphasized that the current vaccines are still highly protective against severe disease and death. In addition, they said that the country has the tools, such as high-quality masks and antiviral treatments, to protect against infections as well as serious illnesses.
To help offer more guidance on how to remain protected against BA.5, Yahoo News spoke to Dr. Monica Gandhi, an infectious disease doctor and professor of medicine at the University of California, San Francisco.
Staying up to date on COVID-19 vaccinations, including boosters, is important
“Vaccines remain our single most important tool to protect people against serious illness, hospitalizations and death,” Ashish Jha, coordinator of the White House’s COVID-19 response said on Tuesday at the briefing. “Staying up to date is essential as we see BA.5 rise across the country,” he added.
Gandhi told Yahoo News that BA.5 seems to evade neutralizing antibodies conferred by the vaccines or even prior infection from other Omicron subvariants such as BA.1, and that this is probably why we are seeing more reinfections. However, she said, our “T-cells, which help us prevent severe disease, are still working.”
T-cells are an important part of the immune system that help fight some viruses. While antibodies, such as those acquired from a vaccine or previous infection, attack a virus as it enters the body, T-cells act as another line of defense once the virus has made it into the body, by preventing the virus from multiplying and causing severe disease.
In a post on the medical website Medscape, Gandhi wrote that “Mild upper respiratory infections will be common as BA.4/BA.5 evade our nasal antibodies.” However, she told Yahoo News that our T-cells’ immunity from the vaccines or prior infection will continue to protect against severe outcomes.
“We absolutely know that [for] severe disease, vaccines are still protecting us against that particular problem, which is the worst problem,” Gandhi said.
Walensky said on Tuesday that the CDC is still collecting data on the vaccine's effectiveness against Omicron BA.5. However, Gandhi pointed to recent data on vaccine effectiveness from South Africa, which suffered a BA.5 wave earlier. According to a report from the largest health care system in that country, two doses of the Pfizer vaccine are 87% effective against hospitalization from BA.5.
Boosters are key to staying protected against BA.5
Infectious disease experts have also stressed the importance of getting boosted now if you are eligible. This is because some studies have shown that vaccine protection against infection and serious outcomes from COVID-19 wanes over time, particularly for those who are older and immunocompromised.
“Those who are older, those who are immunocompromised, those who have multiple medical conditions should be very up-to-date on their boosters, because they're more at risk when there's high amounts of circulating virus for their even mild infection to get worse,” Gandhi said.
Americans who are 50 years or older and those 12 and older who are moderately or severely immunocompromised are now eligible for two booster shots, meaning they can receive up to four doses of the COVID-19 vaccine.
According to CDC data, the risk of dying from COVID-19 for adults aged 50 and older who have received two booster doses is only 25% of the risk for those who have received one booster dose. This data, Jha said, underscores the importance of staying up to date on your COVID-19 vaccines.
People aged 5 and above are also eligible for a first booster. The CDC recommends that those in this age group who received the Pfizer or Moderna vaccine have their booster or third dose at least five months after completing their primary series.
U.S. regulators are also considering offering a second booster shot soon to people under 50 or all adults, to offer more protection to this age group and lessen the impact of the BA.5 wave.
“I know that the FDA is considering this, looking at it. And I know CDC scientists are thinking about this and looking at the data as well,” Jha said on Tuesday.
Should you get a booster now or wait until the fall, when an Omicron-specific vaccine is available?
One concern many Americans have, Gandhi says, is that the current COVID-19 vaccines available are designed to target the spike protein of the ancestral strain of the virus, which first circulated in 2020.
“BA.5 looks very different from the ancestral strain, at least in the spike protein,” Gandhi said, adding that BA.1 [an earlier Omicron subvariant] had 26 to 32 mutations along its spike protein that differed from the ancestral strain, and that BA.5 has even a few more mutations. “It may be why the booster is not helping us avoid mild infections as well as we'd hoped,” she added.
Pfizer and Moderna are both working on a new vaccine formulation designed to target BA.4 and BA.5 Omicron subvariants. These are expected in October, and Jha said Tuesday that the Biden administration had already placed one order with Pfizer for 105 million doses.
However, Gandhi said that getting a booster now if you are eligible — and have not recently recovered from a COVID-19 infection, which she said also offers protection — is a smart choice and does not preclude you from getting another Omicron-specific booster in the fall.
“There has been no evidence that getting vaccines close together is harmful,” Gandhi said.
“Any booster or any exposure broadens your T-cell immunity. So that's a good thing. That just means that there's no harm in it. Absolutely no harm,” Gandhi said, citing a recent study supporting this recommendation.
For those who are under 50 and healthy, however, Gandhi said that waiting for the Omicron-specific vaccine in the fall “is probably prudent” and that in the meantime, people in this group should use all preventive measures, such as masking and testing, to avoid getting infected. “Then you're going to get antibodies that are tailored towards the circulating subvariant,” she said.
For high-risk people, treatments can help prevent severe outcomes
For individuals who are more likely to get very sick from COVID-19, some treatments are available that could reduce their chances of hospitalization and death. One of them is the antiviral pill Paxlovid, which has been shown to reduce the risk of hospitalizations and death by 90%.
The medication can only be prescribed by a health care provider and must be given within five days of symptom onset for it to work effectively, according to the CDC.
Health officials recommend that people talk to a health care provider immediately after testing positive for COVID-19, to see whether they are eligible for any of the treatments available, including Paxlovid.
Americans are also encouraged to visit COVID.gov to find a Test to Treat location to get tested and treated all in one place.
“We have worked very hard to acquire more of these pills than any other country in the world. And we’ve moved quickly to make these treatments widely available at more than 41,000 locations across the country,” Jha said at the Tuesday briefing.
What can I do to prevent getting infected?
Gandhi and U.S. top health officials said that public health mitigation measures such as indoor masking, testing and improving ventilation are crucial in preventing BA.5 infections.
The CDC has developed a tool to check how much virus is circulating in each community, and to help people decide whether or not they should consider masking in indoor or public spaces.
However, some infectious disease experts have warned that the CDC Community Levels map may not offer a full picture of the number of infections and the degree of risk, since many cases are not reported as more people test at home.
Gandhi says wearing a well-fitted, high-quality mask in public places, especially while using public transportation, is a good way to avoid getting BA.5 right now.
Improving ventilation is also important
“We know that improving indoor air quality by improving ventilation, putting in indoor air purifiers — they can make an enormous difference in reducing infections and spread,” Jha said. “If you are a business or a school or any kind of institution that brings people together indoors, please work to improve the quality of that indoor air.”
Finally, testing is a key factor in stopping transmission, Gandhi said.
“If you are going to be around someone vulnerable, for example, or if you've been exposed to someone [with COVID-19], get tested.”
Cover thumbnail photo: CFOTO/Future Publishing via Getty Images