Jul 29, 2022 11:00 AM


Información en español

The Omicron wave of the ongoing COVID-19 pandemic is not over. And the newest variant may be the most contagious strain of the SARS-CoV-2 virus yet. The BA.5 subvariant is now the predominant strain of COVID-19 in the United States, spreading rapidly and driving new infections. BA.5 is a subvariant of the first Omicron strain, also known as BA.1. While scientists continue to learn more about the newest variant, here is what is known:

BA.5 is highly transmissible

According to the Centers for Disease Control and Infection (CDC), Omicron spreads more easily than previous variants of COVID-19. And because BA.5 is a subvariant of Omicron, it’s proving to be more transmissible. The virus has become more efficient at evading the immune system, driving an increase in COVID-19 infections.

BA.5 evades immunity

Breakthrough infections are becoming more common as the SARS-CoV-2 virus continues to evolve and mutate. This is especially true with BA.5. “Each of these subvariants have gotten better than the preceding one at infecting people who have been vaccinated or previously infected,” says Stephen Goldstein, PhD, virologist at the University of Utah Spencer Fox Eccles School of Medicine. Those who have been vaccinated against COVID-19 or who were recently infected with another recent variant are at risk of becoming infected with BA.5.

The good news is that vaccination and booster shots still protect you from becoming severely sick. “It’s really important for people to understand that vaccines aren’t likely to provide long-term protection from getting infected, but they significantly increase the likelihood that your illness will be short, and not severe,” Goldstein says. 

If that’s the case, why can you still be reinfected with BA.5? After you received a COVID-19 vaccine or were infected by the virus, Goldstein explains, your immune system built many layers, among them antibodies and memory T cells that target the virus. If introduced to a different COVID-19 variant, those antibodies don’t recognize the new variant as well because the virus has acquired mutations and looks different. This makes it harder for the immune system to rapidly recognize and block the new virus variant. After infection, the immune system launches another line of defense: memory T cells. Research has shown that these later-acting T cells have remained effective against newer variants and still provide protection from severe illness.  

BA.5 symptoms are similar to previous COVID-19 variants

At this time, symptoms from BA.5 appear to be similar to those caused by other Omicron subvariants. Common symptoms include fever, runny nose, coughing, sore throat, muscle pain, and fatigue. However, Goldstein notes that COVID-19 symptoms appear to be less severe overall compared to previous variants, like Delta. In part, this is because more people have either been vaccinated against or infected by the COVID-19 virus.

COVID-19 vaccines work against BA.5

Vaccines against COVID-19 continue to protect people from developing severe disease, especially for those who receive a booster dose. A COVID-19 booster shot helps maximize your protection. The vaccines also help in preventing hospitalization and death, with rates that are lower for BA.5 than with previous COVID-19 variants.

“There’s definitely a really good reason to stay up to date on vaccines—to get boosted and to get vaccinated,” Goldstein says.

Due to how much SARS-CoV-2 has evolved, the Food and Drug Administration (FDA) advised vaccine manufacturers to update their COVID-19 vaccines beginning in fall 2022 to protect against the Omicron variant. “If BA.5 is still the dominant variant in the fall, then that’ll be a really good match,” Goldstein says. Updating COVID-19 vaccines annually would be similar to the current practice of updating the influenza vaccine on a yearly basis.

Wearing a mask adds more protection

Those with immunocompromised conditions or who are at high risk should continue to wear a good, high-quality mask when indoors or gathering with a large group of people.

The CDC also recommends wearing a mask indoors in public if the COVID-19 community level where you live is medium or high.

“I think we all know people who have been infected—whether they were vaccinated or had previously been infected—and they’re now infected again,” Goldstein says. “If you want to minimize your chances of getting infected with the virus, the best protection is a COVID-19 vaccine, booster, and a high-quality mask.”

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