Roundup: Peak Influenza Season Sees Surge in Flu-Related U.S. Hospitalizations; and More News

Peak Flu Season Arrives as CDC Reports Surging Activity, Hospitalizations

The U.S. Centers for Disease Control and Prevention (CDC) reports that seasonal influenza activity is elevated and flu-related hospitalizations are surging nationwide. Historically, flu activity tends to peak in January and February.

Overall, the U.S. is experiencing its highest level of respiratory illness since at least the 1997–98 flu season, the CDC data shows.

According to the CDC’s most recent update for Week 52, ending Dec. 27, 2025, several key indicators point to continued and elevated flu activity:

• Very High Activity in Much of the Country: Out of all 55 U.S. jurisdictions (including all 50 states), 32 are currently experiencing “very high” levels of outpatient respiratory illness; another 16 states report “high” activity.
• Increasing Hospital Admissions: During Week 52, 33,301 patients were admitted to hospitals with laboratory-confirmed influenza — the highest weekly total so far this season. Hospitalization rates increased to 9.9 per 100,000 population.
• Cumulative Impact: CDC estimates at least 11 million illnesses, 120,000 hospitalizations, and 5,000 deaths from influenza so far this season.
• Positivity Rate: Clinical laboratories reported a 32.9 percent positivity rate for influenza, with 23,271 positive specimens in Week 52.
• Predominant Strain: Influenza A(H3N2) viruses account for more than 90 percent of subtyped influenza A cases reported this season.

Pediatric influenza-associated deaths have also increased. One new death was reported in Week 52, bringing the total for the 2025–26 season to nine. All age groups are experiencing higher illness and hospitalization rates, with older adults and young children most affected.

CDC officials indicate elevated activity is expected to persist for several weeks. While indicators of severe disease remain relatively low, continued monitoring and preventive measures are recommended.

To reduce risk, the CDC continues to recommend annual influenza vaccination for all individuals aged six months and older who have not yet been vaccinated this season. More than 130 million doses of flu vaccine have already been distributed nationwide.

The CDC recommends the following precautions:

• Vaccination: It is not too late to get a flu vaccine. Annual vaccination remains recommended for everyone six months and older.
• Antivirals: Prescription antiviral medications are available and are most effective when started early, especially for high-risk individuals.
• General Precautions: Frequent handwashing, covering coughs and sneezes, and avoiding close contact with sick individuals remain effective at limiting spread.

The CDC also advises monitoring for flu symptoms, including sudden fever, cough, sore throat, and body aches. Antiviral medications can help reduce severity when started promptly.

Study Finds Opioid Use During Pregnancy Has Doubled in the Last Decade

A concerning new study shows opioid use during pregnancy has doubled over the past 10 years, significantly increasing health risks for both mothers and babies. Researchers from Oregon Health & Science University (OHSU) emphasize the urgent need for improved support systems for pregnant patients.

The findings, published in the Journal of Addiction Medicine, analyzed hospital data from more than 5.5 million patients in California between 2008 and 2020, offering one of the most comprehensive looks at opioid use during pregnancy in the U.S.

A Sharp Increase in Diagnosis

The prevalence of opioid-related diagnoses in pregnant patients rose from 0.14 percent in 2008 to 0.33 percent in 2020 — a doubling that mirrors national trends.

“Given the prevalence and seriousness of this issue, we were surprised by the lack of large-scale studies available,” said lead author Jamie Lo, M.D., associate professor of obstetrics and gynecology at OHSU.

Higher Risks for Mom and Baby

The study identified significant complications associated with opioid use during pregnancy.

Risks for infants include:

• Preterm birth (before 37 weeks)
• Respiratory distress
• NICU admission
• Higher infant mortality risk

Risks for mothers include:

• Severe hypertension
• Hemorrhage
• Need for blood transfusions

Barriers to Getting Help

Fear of stigma remains a major obstacle. Researchers stress that addiction should be treated as a medical condition requiring personalized care, not judgment.

Access to treatment remains limited. In Oregon, for example, only one in four residential treatment programs accepts pregnant patients.

The Need for a “Whole-Health” Approach

Standard prenatal care alone is often insufficient. The study calls for a coordinated, wraparound care model involving addiction specialists, primary care providers, and pediatric teams.

“Evidence shows that linking patients to care earlier improves outcomes,” said co-author Kristin Prewitt, M.D.

Is Marathon Running Bad for Your Heart? New Study Offers Reassuring Insights

Long-distance running places significant stress on the body, leading some to question whether marathon training causes lasting heart damage. A long-term study suggests those fears may be unfounded for healthy recreational runners.

Researchers examined the right ventricle — the chamber that pumps blood to the lungs — and levels of troponin T, a protein released during cardiac stress.

What the Study Found

The study followed 152 male recreational marathon runners over 10 years, evaluating heart scans and blood markers before and after a marathon, then again a decade later.

Immediately after racing, researchers observed a temporary reduction in right ventricular function and an expected rise in troponin levels. However, heart function returned to normal within three days.

Ten years later, no long-term damage was found. The post-race troponin spike showed no association with lasting heart dysfunction. Minor age-related changes were observed, but all cardiac measurements remained within healthy ranges.

What This Means for You

For recreational marathon runners, these findings are reassuring. The temporary cardiac stress experienced during endurance events appears to resolve quickly, without lasting harm.

For most healthy individuals, the cardiovascular benefits of consistent running far outweigh concerns about long-term heart damage. In fact, endurance training continues to support overall heart strength and resilience.