New COVID variant is spreading across CA. What are symptoms? Do tests still work?
As summer comes to an end, COVID-19 cases are on the rise again in California.
While respiratory viruses usually peak in the winter, the novel coronavirus can also surge in the warmer months.
Warm-weather COVID spikes are often fueled by travel, indoor gatherings and waning immunity, experts at the Johns Hopkins Bloomberg School of Public Health say.
Here’s what to know about California’s COVID-19 cases, the latest variant symptoms and how to test:
What’s the new COVID-19 variant in US?
Cases of the new coronavirus strain, known as NB.1.8.1, have been increasing statewide since May 1, according to the California Department of Public Health.
State health officials expect the latest COVID variant to become the most common and “fastest growing.”
What are current COVID-19 levels in California?
As of Monday, Sept. 8, COVID-19 cases were increasing in California, according to the latest data.
In the most recent update on Aug. 30, the state health department reported that California had a 12.8% test positivity rate on average over a seven-day period.
This is an increase of 1.8% compared to the previous week, the department said on its website.
Between Aug. 24 and Aug. 30, COVID-19 accounted for 3.9% of hospital admissions and 1.4% of reported deaths.
According to the U.S. Centers for Disease Control and Prevention, viral activity levels for COVID-19 in wastewater are “very high.”
“Wastewater monitoring can detect viruses spreading from one person to another within a community earlier than clinical testing and before people who are sick go to their doctor or hospital,” the CDC said. “It can also detect infections without symptoms.”
Between Aug. 24 and Aug. 30, wastewater testing showed “very high” levels of SARS-CoV-2 in several California counties, including Merced, Sacramento, San Luis Obispo and Stanislaus counties. No data was available for Fresno County.
“If you see increased wastewater viral activity levels, it might indicate that there is a higher risk of infection,” the CDC said.
What are symptoms for latest COVID strain?
Symptoms of the new COVID-19 variant are similar to those of other coronavirus variants, the CDC said.
They include:
- Fever or chills
- Cough
- Shortness of breath or difficulty breathing
- Fatigue
- Muscle or body aches
- Headache
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
- Diarrhea
When should you test for COVID?
Those displaying possible symptoms of COVID-19 should test for the disease immediately, the CDC said.
The CDC said a polymerase chain reaction test, which is taken by a doctor and processed in a lab, is more reliable in detecting if you are negative for COVID.
If you take an at-home test, a negative result may not always be accurate.
“Positive results are very accurate and reliable,” the CDC said about antigen tests. “However, in general, antigen tests are less likely to detect the virus than PCR tests, especially when symptoms are not present. Therefore, a single negative antigen test cannot rule out infection.”
Will at-home tests detect COVID variants?
While the presence of mutations in SARS-CoV-2 can potentially impact test performance, the COVID-19 tests are designed to detect all known variants, according to the U.S. Food and Drug Administration’s website.
“We expect COVID tests to work well against all versions of the virus,” the CDC previously told The Sacramento Bee.
While the Food and Drug Administration’s website states that tests will typically confirm if you have SARS-CoV-2 or one of its strains, the tests cannot identify which specific variant you have.
“The FDA continues to conduct analyses to identify tests for which performance may be impacted for known SARS-CoV-2 variants,” the administration’s website states.
Do at-home COVID tests expire?
According to the federal Food and Drug Administration, all at-home COVID-19 diagnostic tests come with an expiration date printed on the box or packaging.
Such self-administered tests shouldn’t typically be used past this date, the FDA said.
However, these expiration dates can be extended as additional stability data becomes available.
“COVID-19 test manufacturers perform studies to show how long after manufacturing COVID-19 tests perform as accurately as the day the test was manufactured,” the FDA said.
The shelf life of a test refers to the period during which it should perform as expected, starting from the date of manufacture.
The expiration date marks the end of this period, indicating the latest date by which the test is expected to provide accurate results.
How can I tell if my at-home COVID test is still good?
To see if the expiration date of your at-home OTC COVID-19 test has been extended, check the “Expiration Date” column of the list of authorized at-Home OTC COVID-19 diagnostic tests, the FDA said.
Who can get new COVID vaccines? When will shots be available?
The U.S. Food and Drug Administration has approved new COVID-19 vaccines — with new limits on who can receive them.
The shot is available for adults 65 and older. People ages 5 to 64 who have health conditions that put them at higher risk of severe illness are also eligible to receive the vaccine.
In an Aug. 27 news release, Pfizer and BioNTech said the 2025-2026 vaccines were reformulated under FDA guidance to better target the SARS-CoV-2 sublineage LP.8.1 strain currently circulating.
“Shipping of the LP.8.1-adapted vaccine will begin immediately to ensure robust supply and rapid access of this season’s vaccine in pharmacies, hospitals and clinics across the country,” Pfizer and BioNTech said in the release.
While the new 2025–2026 COVID-19 vaccines have been approved by the FDA, availability is still waiting on final guidance from state and federal health officials.
As of Monday, Sept. 8, California pharmacies and health systems were still assessing supply, and vaccination appointments remained on hold.
This story was originally published September 9, 2025 at 7:33 AM with the headline "New COVID variant is spreading across CA. What are symptoms? Do tests still work?."
