Respiratory Diseases Roundup

Pediatric Flu and COVID Vaccines, Age and Menstruation in Long COVID, and RSV Prevention

Miranda Manier, BA

Key Highlights

  • Pediatric flu vaccination remains universal; COVID advice is divided.
  • Long COVID risk is highest at ages 40–59, but lower at 70 and older.
  • Long COVID is associated with abnormal uterine bleeding and cycle-linked symptom severity.
  • Nirsevimab cut RSV-related hospitalizations by two-thirds in infants.

Pediatric flu and COVID vaccine guidance diverge1

As virus season approaches, major medical organizations uniformly recommend influenza vaccination for children aged 6 months and older, with rare exceptions. The CDC and the American Academy of Pediatrics (AAP) advise planning vaccination ahead of the respiratory season; protection develops in roughly 2 weeks, and influenza typically peaks in February. Pregnant individuals are advised to receive the inactivated (injection) formulation rather than the nasal spray. During the 2023–2024 season, the CDC recorded nearly 200 pediatric flu-associated deaths, most in children eligible but not fully vaccinated, underscoring prevention benefits.

COVID-19 vaccine guidance for children currently diverges. The CDC states that healthy children aged 6 months to 17 years may receive vaccination after clinician–family discussion and recommends vaccination for those who are moderately or severely immunocompromised. In contrast, the AAP strongly recommends vaccination for children aged 6–23 months and advises vaccination for older children at parental discretion. Additional groups—including the Infectious Diseases Society of America and regional public-health alliances on the West Coast and in the Northeast—recommend broader pediatric vaccination. A recent ACIP vote favored individual decision-making and did not issue a specific recommendation, contributing to parental uncertainty. Clinicians are advising families to review a child’s risk factors and ensure routine immunizations remain up to date.

Long COVID risk peaks in adults 40 years and older2

A RECOVER-Adult cohort analysis of more than 10,000 participants assessed symptoms 135 days or more after SARS-CoV-2 infection using the Long COVID Research Index. Compared with adults aged 18–39 years, the odds of meeting criteria for likely long COVID were higher in those aged 40–49 years (OR, 1.40; 95% CI, 1.21–1.61) and 50–59 years (OR, 1.31; 95% CI, 1.14–1.51), similar in those aged 60–69 years (OR, 1.09; 95% CI, 0.93–1.27), and lower in those aged 70 years or older (OR, 0.68; 95% CI, 0.54–0.85).

Symptom patterns also varied by age. In adults 70 years or older, differences in fatigue, pain, palpitations, sleep disturbance, and hair loss between infected and uninfected participants were smaller, making these symptoms less likely to specifically indicate long COVID. Cluster analyses showed that anosmia/ageusia and gastrointestinal or cough-related symptoms were more common in older adults, while brain fog–predominant and mixed symptom clusters were less frequent. Findings indicate that both the odds and the presentation of long COVID vary across age groups.

Long COVID linked to menstrual changes3

A UK survey of more than 12,000 participants found that long COVID was associated with abnormal uterine bleeding (AUB). Compared with controls, participants with long COVID reported heavier and prolonged menstrual flow, more intermenstrual bleeding, and higher prevalence of missed periods, while frequency and regularity of cycles were unchanged. Those with acute COVID who recovered reported minimal menstrual disruption. The findings suggest that long COVID increases the likelihood of symptoms that can worsen quality of life and contribute to anemia.

A prospective study of 54 women with long COVID revealed that symptom severity fluctuated across the menstrual cycle, peaking during the perimenstrual and proliferative phases. Biological analyses identified higher serum 5α-dihydrotestosterone and lower endometrial androgen receptor expression in long COVID, with cytokine profiles indicating increased menstrual inflammation. Neutrophil and macrophage aggregates were observed in menstrual endometrium from long COVID participants. Ovarian function appeared preserved, but altered androgen activity and immune responses may contribute to both AUB and symptom exacerbation. Authors recommend integrating menstrual health into long COVID research and management strategies.

Nirsevimab reduces RSV hospitalizations in infants4

A retrospective cohort of 409,723 infants born between February 2024 and January 2025 assessed the impact of nirsevimab during the 2024–2025 RSV season. Of these, 194 422 infants (47.5%) received nirsevimab. RSV-associated hospitalization occurred in 0.4% of treated versus 1.2% of untreated infants (P < .001). The maximum estimated daily hospitalization rate was 2.90 per 100,000 treated compared with 13.84 per 100,000 untreated infants. In Cox models, nirsevimab was associated with substantially reduced hospitalization risk (adjusted HR, 0.23; 95% CI, 0.21–0.26).

ICU admissions (0.2% vs 0.4%) and intubations (<0.1% vs <0.1%) were also lower among treated infants. Limitations included potential loss to follow-up and incomplete maternal vaccination data. Nevertheless, findings align with prior-season results and reinforce nirsevimab as an effective preventive option for infants in their first RSV season and for high-risk older infants, consistent with CDC recommendations.

References
1. CBS News. Should kids get flu and COVID shots this fall? Here’s what to know as some vaccine guidance shifts. CBS News. September 24, 2025. Accessed September 29, 2025. https://www.cbsnews.com/news/kids-flu-covid-shots-fall-2025-vaccine-guidance-shifts/

2. Villarreal AE, Gaugler JE, Yende S, et al. Age-related variation in long COVID prevalence and symptom patterns in community-dwelling adults. J Am Geriatr Soc. 2025. Published online September 9, 2025. doi:10.1111/jgs.70043

3. Taquette A, Sundaram A, Taylor H, et al. The potential bidirectional relationship between long COVID and menstruation. Nat Commun. 2025;16:8965. doi:10.1038/s41467-025-62965-7

4. Pelletier JH, Rush SZ, Robinette E, et al. Nirsevimab administration and RSV hospitalization in the 2024-2025 season. JAMA Netw Open. 2025;8(9):e2533535. doi:10.1001/jamanetworkopen.2025.33535