By mid-August, a sore throat can feel like an out-of-season problem. Yet while Americans return from vacations and children head back to school, COVID-19 is spreading across the country again. According to the Centers for Disease Control and Prevention (CDC)'s latest estimate, based on data through Aug. 12, 2026, infections are growing or likely growing in all 50 states.

The coronavirus adds a familiar illness to a year already crowded with infectious-disease alerts, from measles and Ebola outbreaks to foodborne illnesses linked to jalapeños. The agency’s weekly summary specifically highlights increases across the South and West, while the 50-state estimate shows that infections are also rising in the Northeast and Midwest. Activity remains low in many regions, but the direction is upward nationwide.

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Why COVID-19 Is Spreading This Summer

The regional pattern aligns with a June 2026 CDC outlook, which anticipated more summer transmission in Southern and Western areas that experienced comparatively little COVID-19 activity during the 2025-2026 winter. According to the agency, those regions may now have less recent immunity from infection. The Northeast and Midwest experienced more winter activity and were expected to have smaller summer increases.

That explanation remains tentative. COVID-19 can peak in summer or winter, with timing varying from one region to another. Researchers continue to examine how waning immunity, new variants, human behavior, and environmental conditions interact to shape each wave.

How the CDC Tracks the Summer COVID-19 Wave

The CDC builds its state estimates from emergency department data and models changes in transmission from week to week. One output is R(t), an estimate of how many additional infections arise, on average, from each infected person.

Wastewater offers a separate early indication. Labs can detect viral material released by people with and without symptoms, sometimes before increasing infections become visible in doctors’ offices and hospitals. Wastewater can show whether the virus is becoming more common in a community, but it cannot show exactly how many people are infected.

Traditional case totals have become less complete as more people use at-home tests whose results often remain unreported. To fill those gaps, the CDC compares emergency department visits, lab results, hospital data, and wastewater.

Transmission and severe outcomes are not increasing at the same pace. According to the CDC, national hospitalization peaks have declined since the 2023-2024 winter. Possible reasons include greater population immunity, the absence of a dominant variant with pronounced immune-escape properties, and potentially lower disease severity.

COVID-19 Tests, Treatments and the Next Vaccine

One negative result from a home antigen test can miss an infection in its early stages. The FDA recommends that people with symptoms test again 48 hours later. People without symptoms should take three tests in total, with 48 hours between each one.

People at elevated risk should contact a clinician soon after symptoms appear because Paxlovid must begin within five days and remdesivir within seven, according to the CDC. Separately, the FDA has approved Xocova (ensitrelvir) to help prevent COVID-19 after exposure in people ages 12 and older when started within 72 hours.

CDC guidance advises people with respiratory illnesses to stay home until their symptoms have improved for at least 24 hours and any fever has ended without medication. The agency recommends considering added precautions for another five days.

Variant estimates arrive more slowly than transmission models. According to the CDC’s latest posted estimate, XFG.1.1 represented 29.7 percent of circulating variants during the two weeks ending July 4, 2026. The FDA has selected an XFG strain for the 2026-2027 vaccine, which is intended for use beginning this fall.

Growing transmission still poses a serious risk to older adults and other people more likely to become severely ill. Lower hospitalization peaks do not make every infection low-risk.

This article is not offering medical advice and should be used for informational purposes only.

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Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from the CDC: Current Epidemic Trends (Based on Rt)
• This article references information from the CDC: Respiratory Illnesses Data Channel
• This article references information from the CDC: 2026 COVID-19 Summer Outlook
• This article references information from the CDC: About Wastewater Data
• This article references information from the FDA: Understanding At-Home OTC COVID-19 Antigen Diagnostic Test Results
• This article references information from the CDC: COVID-19
• This article references information from the FDA: COVID-19 Vaccines (2026-2027 Formula) for Use in the United States Beginning in Fall 2026
• This article references information from the CDC: Types of COVID-19 Treatment
• This article references information from XOCOVA: XOCOVA
• This article references information from the CDC: Variants and Genomic Surveillance