COVID-19 cases are experiencing a summer increase in certain parts of the United States, according to health tracking data and expert analysis. While overall national rates are low, wastewater testing shows emerging upticks in several states, primarily in the South and on the West Coast.
Dr. Susan Kline, a professor at the University of Minnesota, noted that CDC wastewater data reveals a rise in COVID-19 detection in multiple states. Specifically, California, Nevada, Hawaii, Florida, Louisiana, and Mississippi are experiencing low levels of COVID activity, while Missouri and Alaska are reporting moderate levels. These trends are more easily observed through wastewater testing due to decreased prevalence of individual testing and reporting.
"I think wastewater testing has become a convenient way to track the trends in a community or in a state because there’s no special lab test required for that," Kline explained. This method is particularly useful as traditional case reporting has become less common following funding changes and reduced at-home testing.
Experts suggest that this summer increase is not entirely unexpected, aligning with patterns observed in previous years. Dr. Neil Maniar, a public health professor at Northeastern University, pointed out that late June and early July often mark the lowest rates, followed by an increase in August. Last year saw a peak in late August and early September, a possibility for this year as well. COVID-19 cases typically see another peak in the winter around December and January.
Several factors may contribute to this seasonal ebb and flow. Maniar cited a general decrease in COVID-19 vaccination rates, leading to a larger susceptible population. Data from the CDC indicates that only 17.5% of American adults and 8.9% of children received the 2025-2026 COVID vaccine. Additionally, increased summer travel, which involves more crowded transportation and public spaces, can facilitate the spread of the virus.
Public health recommendations remain consistent for protecting against respiratory illnesses. Experts advise frequent hand-washing, staying home when sick, and avoiding close contact with individuals exhibiting symptoms like coughing or sneezing. Wearing a mask in crowded indoor settings, such as on planes or trains, is also recommended.
If symptoms arise, taking a COVID-19 test is advised, as current at-home tests can detect circulating variants. Individuals who test positive and are at high risk may be eligible for antiviral treatments like Paxlovid, which should be started early in the illness to reduce the risk of long COVID and speed recovery.
Vaccination continues to be the primary defense. While the updated 2026-2027 COVID vaccine is anticipated for the fall, the 2025-2026 formulation is currently available. Dr. Kline suggests waiting for the more updated vaccine if possible, as it is designed to better match currently circulating strains. However, she noted potential exceptions, such as for high-risk individuals or those with upcoming travel plans, recommending consultation with a doctor.
"The goal of the vaccine from the beginning has been to reduce the likelihood of hospitalization and death from COVID, and that’s still the case," Maniar added. Health officials anticipate the new vaccine formulation to be available in September or October, similar to the annual flu vaccine.
Beyond COVID-19, health officials are also noting a significant increase in measles cases, underscoring the importance of routine vaccinations. Maniar emphasized that vaccines are critical for preventing widespread outbreaks of illnesses like flu and COVID-19, stating, "We have the means to prevent massive flu outbreaks, and COVID outbreaks, even, for that matter. So, we’re fortunate to have these tools, and I think we should use them."