BA.5 currently makes up 54 percent of new cases, with its sister subvariant, BA.4, accounting for about 16 percent of recent infections. In Europe, BA.4 and BA.5 are driving a summertime COVID-19 surge. Analysis of data by The New York Times showed that infections climbed to 57 cases a day per 100,000 people (as of July 6) from 33 cases a day per 100,000 people just two weeks earlier. In a media briefing on July 6, Dr. Michael Ryan, MPH, the executive director of the World Health Organization’s Health Emergencies Program, said that many European countries have seen a rise in hospitalizations but not an increase in intensive care admissions.
BA.4 and BA.5 May Be the Most Contagious COVID-19 Viruses Yet
BA.4 and BA.5 have proven to be especially adept at eluding protective antibodies from vaccination or prior infection. In an interview with Nexstar Media Wire, Peter Chin-Hong, MD, an infectious-disease expert at the University of California in San Francisco, said, “The superpower of BA.4 and BA.5 is, if you had omicron in January, you’re still going to be susceptible to getting BA.4 and BA.5. It’s the escape artist of COVID, the Houdini, because the spike protein looks so different, even [compared] to BA.1. The front guards — the antibodies — are not recognizing it.” A study published in the journal Nature on July 5, based on lab studies headed by a team at Columbia University in New York City, indicated that BA.4 and BA.5 are four times more resistant to antibodies from three vaccine doses than BA.2, a previous version of omicron that was dominant in the United States in April. “Our study suggests that as these highly transmissible subvariants continue to expand around the globe, they will lead to more breakthrough infections in people who are vaccinated and boosted with currently available mRNA vaccines,” said the study’s lead author, David Ho, MD, the director of the Aaron Diamond AIDS Research Center at Columbia University, in a press release.
COVID-19 Symptoms Overall So Far Tend to Be Mild
William Schaffner, MD, an infectious-disease specialist and a professor of preventive medicine and health policy at the Vanderbilt University School of Medicine in Nashville, Tennessee, views the spread of BA.4 and BA.5 as a glass half-empty, glass half-full situation. “Yes, the BA.4 and BA.5 variants are not as well covered by the current vaccines, but the current vaccines do continue to provide substantial protection against serious disease caused by these variants,” says Dr. Schaffner. “The vaccines continue to keep people out of the hospital.” Older, unvaccinated people may be at risk of serious illness from the new subvariants. In Nevada the week ending July 8, hospitalizations in Clark County rose for the second week in a row, according to the state’s department of health and human services, with unvaccinated people who are 70 and up accounting for the majority of admissions. Based on data from the Zoe COVID Symptom Study (in which people report symptoms via phone app), the most common signs of coronavirus infection in England (where BA.4 and BA.5 also dominate) are runny nose, sore throat, headache, persistent cough, and fatigue. Under a third of study respondents indicated that they had a fever.
Americans Are Urged to Take Preventive Measures to Avoid COVID-19
The CDC regularly updates county-by-county information showing where COVID-19 transmission is highest. (A COVID-19 County Check tool on the website allows you to plug in details about your location to check the status in the area where you live.) If you live in an area of substantial or high transmission, the CDC urges you to wear a mask in indoor public places if you are 2 or older. In areas with high numbers of COVID-19 cases, you should consider wearing a mask in crowded outdoor settings and for activities requiring close contact with others who are not fully vaccinated. If you live in a high-transmission zone, the CDC also encourages you to stay six feet apart from people not in your household. The health agency reminds the public that even people without symptoms can spread the virus. People in high-risk groups need to take extra precautions. These groups include everyone age 65 and older; those younger than 65 who have any underlying illness, such as heart or lung disease or diabetes; and anyone who is immunocompromised.
Living With a Mutating Virus Might Mean Updating Vaccine Formulations Regularly
Dr. Ho said the development of new vaccine boosters aimed at BA.4 and BA.5 offers hope to improve protection against infection and severe disease. Updated formulations are expected to be ready this fall. Looking further into the future, scientists will need to continually develop new vaccines and treatments that can anticipate the ongoing evolution of the virus. “Now that we have entered the COVID endemic phase, we’ll have to learn how to live with this mutating virus,” says Schaffner. “There are lessons to be learned from how we cope with influenza. Our public health surveillance system will have to keep up with the changes in the COVID virus as it already does with influenza, and then our vaccines will be updated, again as we do with influenza. It would not surprise me if we will be getting annual COVID vaccinations along with our annual flu shots.”
