Why Are COVID-19 Cases Spiking Again?

We answer your questions about the summer spread and how to protect yourself.

It’s summer, and RSV and flu have come and gone. But, as ever, COVID-19 is different. Even though the pandemic may be behind us, the virus is once again surging in the U.S.

Here’s what to know about the current spike in COVID-19.

How serious is it?

COVID-19 seems to be settling into a pattern of two peaks a year: one in the winter and one in the summer. According to the latest data from the end of June, rates of positive COVID-19 tests from labs (which represent only a small fraction of overall cases), increased by nearly 1% from June 23-29. Emergency room visits for COVID-19 jumped 23% during that same time period, and hospitalizations for the disease increased by 13% from June 9-15. Signs of the COVID-19 virus in wastewater—which provides among the most accurate, real-time snapshots of cases—have been increasing since May. Just before July 4, four states—Florida, New Mexico, Nevada, and Utah—reported very high levels of the virus in wastewater samples collected from sewage facilities.

The good news is that while the number of cases is climbing, deaths from COVID-19 continue to drop. In the last week of June, deaths from COVID-19 declined by 25%.

Why are COVID-19 cases increasing?

The rise in cases is due to a number of factors. First, people’s immunity to the virus is waning; only 22% of people in the U.S. received the most updated vaccine, which became available in the fall. Second, the newest variants are mutating to spread more easily between people. That means more people are likely to get infected.

Read More: The Vaccines You’ll Need This Fall and Winter

But so far, the virus does not seem to be causing more severe disease. “The latest data on COVID-19 show that it is now starting to settle in and have similar kinds of statistics to influenza, meaning hundreds of thousands of hospitalizations and tens of thousands of deaths every year,” says Dr. Paul Offit, director of the vaccine education center at Children’s Hospital of Philadelphia and a member of the U.S. Food and Drug Administration’s vaccine expert committee. And similar to flu, the people most severely affected are the elderly and those with weakened immune systems.

Which variants do I need to worry about now?

With a virus that mutates as quickly as SARS-CoV-2 does, keeping up with the alphabet-soup names of the newest variants is a daunting task. The latest strains are still from the Omicron family, and KP.2, and KP.3—two examples of the circulating ‘FLiRT’ variants, named for the locations of their particular mutations in the virus’ spike protein—are dominating new infections in the U.S. right now. Since June, FLiRT variants have accounted for more than 60% of COVID-19 infections in the U.S. The newest data from WastewaterSCAN found that FLiRT variants account for 55% of the COVID-19 variants found in wastewater samples from across the country, and the concentration of the virus in samples is more than double what it was in June 2023.

For now, it doesn’t appear that these mutations are making the virus more dangerous to human health or enabling the virus to cause more severe disease. But health experts are monitoring cases to learn more about these latest changes.

My recent bout with COVID-19 was worse than my previous infections. Is the virus getting stronger?

People who have been infected recently have experienced symptoms of fever, coughing, malaise, and even intestinal discomfort. But having more severe symptoms than you may be used to doesn’t necessarily mean you’ve encountered a more virulent strain. Dr. Robert Murphy, professor of infectious diseases at Northwestern University Feinberg School of Medicine, says that worse-than-usual bouts with COVID-19 could be due to the fact that their immunity is much lower now than what it was in previous years when more people were more recently vaccinated. The low uptake of the newest vaccine means fewer people have the strongest possible protection against the latest variants. “Vaccines gives you better immunity than getting the disease,” says Murphy. “Vaccines provide a controlled exposure that gives you a stronger immunologic response than from an infection.”

Is it still worth getting vaccinated?

Offit says vaccines are critical for people who are at high risk of developing complications from COVID-19, and staying up to date can protect them from being hospitalized. But it’s important to set realistic expectations. “The goal of the vaccine is to keep you out of the hospital, to keep you out of the intensive care unit, and to keep you out of the morgue,” he says. “That’s the goal—it’s not to protect you against mild disease.”

Read More: A Combined Flu and COVID-19 Shot May Be Coming

The CDC’s expert vaccine committee recently recommended an updated COVID-19 vaccine for everyone six months and older for the coming fall and winter season. The shot will be revised to target the KP variant currently circulating, which should improve the shot’s ability to minimize symptoms and severe COVID-19 disease.

Should I start wearing masks again in public?

With a more transmissible virus circulating, some people should consider it. “If I were in a high-risk group, such as being older or having a high-risk medical condition, and I’m in a large group of people I didn’t know—like on an airplane—I think it’s reasonable to wear a mask,” says Murphy. That consideration should also apply to people who are sick. “I think anyone who has a respiratory illness should stay at home,” says Offit. “And if you can’t stay at home, you should wear a mask. If you’re in a high-risk group, get tested,—and if you have COVID-19, take an antiviral [like Paxlovid].”