US flu activity last week declined for the third week in a row, but major impacts are still being felt at hospitals and outpatient clinics, with 16 more pediatric flu deaths reported, the US Centers for Disease Control and Prevention (CDC) said today in its latest update.

With the nation still in the grips of a high-severity season for the first time since 2017-18, test positivity for flu last week was still high, at 18.9%, but shows a declining trend. Nationally, the percentage of outpatient visits for flulike illness—currently just shy of 5%—has been above the national baseline for 14 weeks in a row, and all areas of the country remain above their regional baselines.

Though the nation is in the latter part of the flu season, when influenza B activity often spikes, 96% of positive flu tests at public health labs last week were influenza A. Of subtyped influenza A viruses, 54.4% were the 2009 H1N1 strain and 45.6% were H3N2.

Hospitalizations tracked through the FluSurv-NET show that the cumulative rate last week was the highest since the 2010-11 season, and the CDC's National Healthcare Safety Network (NHSN) Hospital Respiratory Data show that more than 29,500 people were hospitalized for flu last week, showing a downward trend.

Overall deaths from flu declined, but again outpaced COVID-19 deaths. The 16 newly reported pediatric flu deaths pushed the season's total to 114. That compares with 187 deaths for all of 2022-23 and 207 last season. Of the latest deaths, 15 were linked to influenza A and 1 to influenza B. Of 9 subtyped influenza A samples, 5 were H1N1 and 4 were H3N2.

COVID wastewater detections now at low level

For COVID, test positivity remains stable, and emergency department visits and hospitalizations continue to decline, the CDC said in its weekly respiratory virus update. The percentage of deaths from COVID, at 1.1%, was similar to the previous week.

Wastewater detections of SARS-CoV-2 declined from the moderate to the low level, with the highest levels in the South.

Five countries reported polio cases this week, including Pakistan, which reported three cases of wild poliovirus type (WPV1), according to the latest update from the Global Polio Eradication Initiative (GPEI).

The three WPV1 cases, with onset of paralysis in January and February, were in Sindh and Punjab provinces. The cases bring the country's total WPV1 cases in 2025 to six. Pakistan is one of two countries (along with Afghanistan) where wild poliovirus is still endemic.

The other polio cases reported this week involved circulating vaccine-derived poliovirus type 2 (cVDPV2). Among the affected countries is Nigeria, which reported 7 cVDPV2 cases (4 from 2024 and 3 from 2025) in Kano, Borno, and Jigawa provinces, bringing its 2024 total to 98 cases and its 2025 total to 3 cases. GPEI said it recently sent a high-level delegation to Nigeria to discuss the country's efforts to stop cVDPV2 transmission.

Chad reported 4 cVDPV2 cases, 2 having onset of paralysis in November and 2 in January, bringing its total number for 2024 to 37 cases and for 2025 to 2. Cameroon reported a cVDPV2 case with paralysis onset in December, bringing its total for 2024 to 3 cases. Djibouti reported its first cVDPV2 case of 2025 after confirming none in 2024.

• The US Department of Agriculture (USDA) has eliminated two of its food safety advisory committees that have been in place for decades, Food Safety News reported today. The USDA notified members of the two groups—the National Advisory Committee on Microbiological Criteria for Foods and the National Advisory Committee on Meat and Poultry Inspection—on March 6. Brian Ronholm, director of food policy at Consumer Reports, said the expert panels have regularly provided expertise to federal health agencies and that the failure to recognize and leverage their scientific advice is "dangerous and irresponsible."
• The UK Health Security Agency (HSA) today said health officials are tracing contacts of a person from Nigeria who visited England while sick with Lassa fever at the end of February. Officials said the person was diagnosed as having the illness when he or she returned to Nigeria. The HSA said Lassa fever doesn't spread easily among people and that the risk to the public is very low. The disease is endemic in some West African countries. Lassa virus can spread to people who are exposed to food or household items contaminated by urine or feces from infected rats. The United Kingdom reported its last imported Lassa fever case in 2022.
• Uganda today received 2.278 million doses of malaria vaccine, which it will use to immunize people in 105 of the country's districts that are in the high- and moderate-risk categories, Gavi, the Vaccine Alliance, and the health ministry said in a joint statement today. The vaccine will be incorporated into Uganda's routine vaccine schedule starting in April, targeting kids younger than 2 years old, and will eventually be rolled out the whole country. The vaccine delivery was made by Gavi with co-financing from Uganda's government. Seventeen African countries have introduced the vaccine. Six to eight more are expected to introduce malaria vaccination later this year.