The BA.5 Variant Is Now the Most Contagious Strain to Date — What to Know

As the COVID-19 pandemic continues, unfortunately, so does the rise of new and emerging variants. The latest to dominate headlines is the BA.5 variant. According to recent data from the Centers for Disease Control and Prevention (CDC), the variant has accounted for 54 percent of the country's new cases, while BA.4, another emerging variant, makes up almost 17 percent of the new cases.

The BA. 5 variant is reportedly the most contagious one to date, per Yale Medicine. The Food and Drug Administration has recommended that the next round of boosters be targeted to combat BA.4 and BA.5 "so that the modified vaccines can potentially be used starting in early to mid-fall 2022," said Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and Research, in a statement.

So what makes BA.5 so hard to avoid? We spoke to infectious-disease expert Amesh Adalja, MD, senior scholar at the Johns Hopkins University Center for Health Security, to learn more about the dominant strain.

"BA.5 is an omicron variant of SARS-CoV2," Dr. Adalja tells POPSUGAR. "It is likely a descendent of the BA.2 variant and has a cluster of mutations that make it very efficient at transmitting between people and avoiding some of the protection prior infection and vaccines provide." It's this combination of mutations that gives BA.5 its high degree of transmissibility.

The symptoms of BA.5 aren't very different from other variants, Dr. Adalja says. "It's all a spectrum of upper respiratory symptoms, and one cannot tell the difference between variants based on clinical symptoms." Coughing, sore throat, fatigue, runny nose, headaches and/or muscle pains can all be expected.

Unfortunately, the BA.5 variant is rather successful at reinfection. "BA.5 is able to reinfect those with immunity from prior infections, including prior omicron infection," Dr. Adalja says. What's more, there is some data that shows reinfection can "lead to negative consequences."

A recent study from the VA Health System based on the health records of more than 5.6 million people found that "compared to people with first infection, reinfection contributes additional risks of all-cause mortality, hospitalization, and adverse health outcomes in the pulmonary and several extrapulmonary organ systems." So it's important to try to avoid getting COVID, even if you've already had it and recovered from it.

Current vaccines work to "protect against what matters most," Dr. Adalja says. That includes severe disease, hospitalization, and death. Still, experts know that the "effectiveness of primary vaccination wanes over time against certain variants, including omicron," Dr. Marks admitted in his recent statement.

To ensure that the population continues to be as protected as it can be, the FDA has advised manufacturers to focus their next round of boosters on the most dominant variants. "As we move into the fall and winter, it is critical that we have safe and effective vaccine boosters that can provide protection against circulating and emerging variants to prevent the most severe consequences of COVID-19," Dr. Marks said.

Despite the rise in BA.5 cases, Dr. Adalja does not anticipate that mask mandates or other strict social-distancing rules will resume. "Those types of government measures do not make sense in the current context and especially if hospitals are not compromised," he says.

The best way to protect oneself is to be vaccinated and boosted, especially if you are a high-risk individual (e.g., older adults, the immunocompromised, pregnant people, or those who have other medical conditions), Dr. Adalja says. Those in high-risk situations — like extremely crowded indoor areas — should wear a mask.

High-risk individuals should also consider Evusheld, a preventative treatment for COVID-19 given to those who struggle to make antibodies and have a plan to be prescribed Paxlovid or receive a monoclonal antibody if positive, Dr. Adalja says.