Covid-19 Summer Wave In The US: 25 States See Significant Increase In Cases, Reports CDC

From Florida to Texas, a total of 25 US states are witnessing a surge in Covid-19 cases. According to the US Centers for Disease Control and Prevention (CDC), as of July 8, 2025, Covid-19 infections are growing or are likely to grow in 25 states, signalling the onset of a "summer wave." The CDC has attributed this resurgence of Covid-19 infections to fading immunity and emergence of new covid variants.

According to a Johns Hopkins report, several virological, behavioural, and environmental factors drive summer Covid-19 waves. Additionally, human behaviours like increased use of air-conditioners, frequent social gatherings and travelling during the summer holidays also trigger transmission of the virus.

New Covid-19 variants driving 2025 summer wave

An uptick in Covid-19 cases in 25 US states has been linked to the rapid circulation of new covid sub-variants - XFG and NB.1.8.1.

About NB.1.8.1 and XFG

'Nimbus,' scientifically known as NB.1.8.1, is an Omicron sub-variant. It is known to cause mild to moderate upper-respiratory symptoms. However, the variant gained attention due to its distinctive and extremely painful sore throat symptoms. Most infected individuals have described the severity of the throat pain as "razor blade throat". According CDC, Nimbus accounted for approximately 37% of US cases within two weeks as of June 7. The NB.1.8.1 sub-variant does not cause serious illness. However, it appears to be highly transmissible.

XFG 'stratus' covid variant

XFG Covid-19 variant (nicknamed Stratus) is spreading rapidly across the globe. The World Health Organisation has designated XFG as a 'Variant Under Monitoring,' which means that the variant or sub-variant needs prioritised attention. Several reports suggest that XFG could become the next dominant variant worldwide. XFG is also a descendant of the Omicron family.

Some infected individuals have also reported hoarseness or a rough, raspy voice.

Other than these distinct symptoms, both XFG and NB.1.8.1 are likely to cause omicron-like symptoms, including congestion, fatigue, mild cough, fever, loss of taste and smell, runny nose, loss of appetite and muscle aches. Less common symptoms include diarrhea and nausea.

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