Activity from the three main respiratory viruses continues to decline in the United States, with one of the main flu markers—outpatient visits for flulike illness—now below the national baseline for the first time since October, the Centers for Disease Control and Prevention (CDC) said today in its latest updates for flu, COVID, and respiratory syncytial virus (RSV).

Only one jurisdiction—North Dakota— reported high respiratory virus activity last week, down from six the previous week, the CDC said in its respiratory virus snapshot. No locations reported "very high" activity.

In its weekly FluView report, the CDC said activity is still elevated but continues to decline, with other indicators such as test positivity and hospitalizations also heading downward. Three areas of the country are still above their regional baselines for outpatient visits: the upper and central Midwest and the Northeast. 

Five more pediatric flu deaths were reported, raising the season's total to 138. The deaths occurred between the middle of February and the end of March. Two were due to influenza A, and three were linked to influenza B.

COVID wastewater levels remain low

COVID data updates today from the CDC show declining trends for severity markers such as hospitalizations and deaths as well as for early indicators, which include emergency department visits and test positivity. Also, the CDC said wastewater SARS-CoV-2 detections remain low.

Also today, the CDC updated its SARS-CoV-2 variant proportions, which show that JN.1 is still dominant, at 83.7%, with slowly rising proportions of one of its offshoots, JN.1.13. The proportion of JN.1.13 viruses rose from 6.5% to 9.1% over the past 2 weeks.

In JAMA Network Open, a study today demonstrates that receipt of the recommended combined seven-vaccine series in US kids increased from 22.5% in 2011 to 35.6% in 2021. But improvements in on-time vaccination rates were lower for children from lower-income families and those without private health insurance, showing a link between vaccine coverage and household income.

The immunization schedule recommended in the United States says vaccinations, including diphtheria-tetanus-acellular pertussis (four doses), inactivated poliovirus (three doses), measles-mumps-rubella (one dose), hepatitis B (three doses), Haemophilus influenzae type b (three or four doses, depending on brand), varicella (one dose), and pneumococcal conjugate (four doses) should be provided at birth and ages 2, 4, 6, 12 to 15, and 15 to 18 months.

Increase in on-time vaccination highest among wealthier families 

The study was based on vaccination timeliness for US children aged 0 to 19 months using data from the annual National Immunization Survey–Child (NIS-Child) conducted from 2011 through 2021. Included in the survey were 179,154 children, 31.4% of whom lived above the federal poverty level (more than $75,000 in annual family income), 32.4% lived at or above the poverty level ($75,000 or less), and 30.2% lived below the poverty level.

Children whose families had more than $75,000 in annual income had a 4.6% (95% confidence interval [CI], 4.0% to 5.2%) mean annual increase in on-time vaccination. The mean annual increase was 2.8% (95% CI, 2.0% to 3.6%) for children living at or above the poverty level, and 2.0% (95% CI, 1.0% to 3.0%) for children living below the poverty level.

The rate of improvement was greater for children from higher-income families and with private health insurance.

"The rate of improvement was greater for children from higher-income families and with private health insurance, compared with children from lower-income families or those with Medicaid insurance, respectively. As a result, disparities in vaccination timeliness by socioeconomic indicators widened over the 11-year period," the authors said.

The Wisconsin Department of Natural Resources (DNR) yesterday confirmed chronic wasting disease (CWD) in a wild deer in Waushara County for the first time. 

The deer was found dead in early February in the town of Wautoma, within 10 miles of the Marquette and Portage county borders. It was a 3-year-old buck.

CWD is an always-fatal infectious disease that affects the brain and nervous system of deer, moose, elk, reindeer, and caribou. It has not yet jumped to humans, but officials warn people not to eat the meat of infected animals. The Wisconsin DNR first detected the disease in 2002.

The new positive test lifts the number of Wisconsin counties that have reported CWD or are considered "CWD affected" to 63 of 72.

Renewed baiting, feeding bans

Because of the detection, Waushara County will renew a baiting and feeding ban that was already in place because of CWD-positive tests in neighboring counties. Marquette and Portage counties already have 3-year baiting and feeding bans in place from earlier detections, so the new test result will not affect those counties.

The DNR and the Waushara County Deer Advisory Council will host a public meeting to provide more details, including information about CWD across the state and testing efforts in Waushara County.

"Baiting or feeding deer encourages them to congregate unnaturally around a shared food source where infected deer can spread CWD through direct contact with healthy deer or indirectly by leaving behind infectious prions in their saliva, blood, feces and urine," the DNR said in yesterday's news release.

Many younger people in high-income New York City neighborhoods accessed COVID-19 vaccinations before they were eligible, risking the lives of older people in low-income areas by pushing them down the queue, according to research in the Journal of Urban Health.

Led by researchers at the University of Witwatersrand in South Africa and Columbia University, the study used linked data from the Census Bureau and New York City Health. 

Starting on December 14, 2020, New York administered vaccines to high-risk hospital workers, expanding to adults 70 years and older on January 4, 2021, 60 and older on March 10, 50 and older on March 23, and those 30 and older on March 30.

Older age greatest risk factor for COVID death

In the first 3 months of COVID-19 vaccine availability, low-income neighborhoods with higher percentages of people 65 years and older had lower vaccine coverage (average vaccination rate, 52.8%; maximum coverage, 67.9%) than higher-income areas (average vaccination rate, 74.6%; maximum coverage in the wealthiest quintile, 99%). Over the year, low-income areas also had higher death rates.

If New York had focused limited vaccine supply on low-income areas with high proportions of residents 65 or older, overall mortality might have been lower.

Despite limited vaccine availability, many younger people—especially in high-income neighborhoods—jumped the queue to get vaccinated before they were eligible (average coverage, 60% among residents 45 to 64 years in the most affluent quintile). A year later, when vaccines were broadly available, older residents' median vaccine uptake was 87%, including in the poorest area. 

"Our analysis provides clear evidence of why U.S. policymakers must target their distribution approach to providing access to lifesaving technologies in short supply, focusing first on those most at risk of severe morbidity and mortality," lead author Nina Schwalbe, of Columbia University, said in a Columbia news release.

The greatest risk factor for COVID-19 death was older age, the authors noted.

"When rolling out a new vaccine, policymakers must account for local contexts and conditions of high-risk population groups," they wrote. "If New York had focused limited vaccine supply on low-income areas with high proportions of residents 65 or older, overall mortality might have been lower."

• A recent human H9 avian flu case in Vietnam, the country's first, has now been confirmed as H9N2, the US Centers for Disease Control and Prevention (CDC) said today in an update. The 37-year-old man lives near a poultry market, though there were no reports of sick or dead birds, according to earlier report. The CDC said the patient, who had underlying health conditions, remains hospitalized for monitoring and treatment. It added that H9N2 infections in people, typically mild and limited to the upper respiratory tract, remain sporadic, with more than 100 cases reported globally since 1998. The virus circulates in poultry as a low-pathogenic virus in many world regions and is the most commonly identified avian flu virus in Vietnam.
• China has reported a third human H10N3 avian flu case, the European Centre for Disease Prevention and Control (ECDC) said today in its weekly communicable disease update, which cites an April 10 preprint report on the case from a team from China. The patient is a 51-year-old man from Yunnan province who had contact with poultry before he became ill in late February. He was hospitalized on March 6 and remains in critical condition. No other cases among his contacts were identified. The two earlier cases were in Jiangsu province in 2021 and in Zhejiang province in 2022. All three patients infected with H10N3 had severe illnesses. 
• One country reported a new polio case this week, Afghanistan with its second wild poliovirus type 1 (WPV1) case of the year, the Global Polio Eradication Initiative (GPEI) said in its latest weekly update. Afghanistan is one of two countries where WPV1 is still endemic. The latest case involves a patient from Nuristan province in the eastern part of the country.