Keep a sharp eye out for COVID-19 symptoms now that Fourth gatherings have passed, experts say

Fourth of July crowds and travel could lead to an uptick in coronavirus infections, experts said.Craig F. Walker/Globe Staff

With Fourth of July weekend celebrations in the rearview mirror, people should keep an eye out for possible symptoms of COVID-19, experts said Tuesday.

“After a holiday, we see increases in cases because people are more likely to gather in larger groups, spend more time indoors at larger gatherings. Those are conditions that increase the rates of SARS-CoV-2 transmission.” said Dr. Sabrina Assoumou, an assistant professor of medicine at Boston University School of Medicine and an attending physician in the section of infectious diseases at Boston Medical Center.

Holiday travel can also contribute to COVID-19 case increases, she said, noting the situation in a crowded airport where many people aren’t wearing masks.

“It’s definitely a time to be more vigilant,” she said.

She said she recommended that people who have been in higher-risk settings should look out for COVID-19 symptoms such as fever, runny nose, cough, and fatigue.

If symptoms develop, people should get tested to find out if they have COVID-19, she said.

Even if a first rapid test is negative, she recommended, people should mask up until taking a second test two or three days later. If they continue to be worried after a second negative rapid test, they could consider getting a PCR test, she said.

Since people can have COVID-19 and be asymptomatic, people who have no symptoms could also decide to take a test two or three days after they’ve possibly been exposed, she said, particularly if they plan to be in contact with vulnerable people like the elderly.

The Boston Public Health Commission tweeted a strong recommendation that people who attended a Fourth of July gathering test for COVID-19.

If you attended a gathering this past weekend, we strongly recommend you test for COVID-19. The @US_FDA has extended the shelf life for all iHealth at-home tests with expiration dates on or before 9/29/2022. These tests are still accurate and good to use! pic.twitter.com/gct2b9oFWy

— Boston Public Health (@HealthyBoston) July 5, 2022

The holiday arrived as concerns have been growing about the arrival of the new Omicron subvariants BA.4 and particularly BA.5, which are highly transmissible and appear to be better able to evade the immunity people have built up from getting sick from COVID-19 previously or getting vaccinated.

The new subvariants are likely to cause an increase in cases, Assoumou said. BA.4 and BA.5 accounted for an estimated 17.8 and 41.6 percent of cases, respectively, in New England in the week ended Saturday, according to the Centers for Disease Control and Prevention. The Broad Institute of MIT and Harvard estimated last week that by mid-July the two variants will account for over 90 percent of cases in Massachusetts.

But Assoumou also emphasized that people can protect themselves.

“We’re not back in 2020. We’re not helpless,” she said. “We have the tools.”

She recommended people get vaccinated, get boosted, wear masks in indoor public settings, get tested, and make sure to use anti-COVID-19 medications if they’re at high risk of complications from the virus.

Matthew Fox, a professor of epidemiology and global health at the Boston University School of Public Health., said an increase in cases could be ahead.

“With BA.5 being so transmissible and evading prior immunity and with so much travel and reduced vigilance, I do think there is a possibility we see an infection bump spurred by this holiday weekend,” he said.

“The good news is that many events were/are outside so hopefully that mitigates a bigger impact, but I do think people should be monitoring for symptoms, testing if they have any concerns, and taking more precautions,” he said.

Andrew Lover, an assistant professor of epidemiology in the School of Public Health and Health Sciences at the University of Massachusetts Amherst, said it’s “quite possible we’ll see a spike this coming week and next from the Fourth. BA.5 is rising fast in many places.”

“There’s some suggestion from Italy and Germany that it may cause fairly severe symptoms, and hospitalizations are rising in several European countries,” Lover said in an e-mail. “However, we don’t have a good handle on any differences in symptoms yet.”

“Testing whenever possible should be a high priority for anyone with symptoms,” he said.