COVID vaccination in first half of menstrual cycle tied to temporarily longer cycles

News brief
Ovulating woman looking at phone app
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Women vaccinated against COVID-19 in the first half of their menstrual cycle (follicular phase) are more likely to see slight, short-term changes in cycle length than those vaccinated in the second half (luteal phase), concludes a large study published in Obstetrics & Gynecology.

A team led by Oregon Health & Science University (OHSU) parsed data on the effect of COVID-19 vaccination timing during the menstrual cycles of 19,497 women of reproductive age using a birth-control app. Menstrual-cycle outcomes among the vaccinated women were compared with those of an unvaccinated control group. Most participants (80.1%) were younger than 35 years and were from North America (28.6%), Europe (33.5%), or the United Kingdom (31.7%).

In the follicular phase of menstruation, eggs begin to develop in small sacs called follicles, one of which could be released for fertilization during ovulation, while the luteal phase occurs after ovulation.

1-day average difference

Women who received their first or second COVID-19 vaccine dose in the follicular phase noted that their cycle lasted, on average, 1 day longer than before vaccination (first dose, 1.0 day; second dose, 1.1 days). Those vaccinated in the luteal phase and unvaccinated participants saw no change in cycle length (first dose, −0.09 days; second dose, 0.06 days; unvaccinated notional first dose, 0.08 days; second notional dose, 0.17 days).

We hope this work helps validate the public's experiences and ease fears and anxiety around vaccination.

The biological mechanisms for the menstrual changes, which the authors said are not clinically significant for most women, may have to do with the body's immune response to vaccines, lead author Alison Edelman, MD, MPH, of OHSU, said in a university news release.

"Understanding these changes on a population level allows us to more effectively counsel patients about what to expect with a COVID-19 vaccine," she said. "We hope this work helps validate the public's experiences and ease fears and anxiety around vaccination."

US measles cases rise to 41

News brief

Since its last update on February 23, the US Centers for Disease Control and Prevention (CDC) last week reported 6 more measles cases, raising the nation's total so far this year to 41. Against a backdrop of rising global activity this winter, measles infections in the first months of the year are gaining quickly on the 58 cases the CDC reported for all of 2023.

atypical measles
CDC/ Dr. Patterson, Chief of Pediatrics, Henrietta Egleston Hospital

The CDC reported 1 more affected state, Michigan, raising the number of jurisdictions reporting cases to 16.

More cases in Michigan

In related developments, two more cases have been reported in Michigan, raising the state's total to three. Officials recently reported the state's first case since 2019, which involved a child in Oakland County.

One of the new cases involves a detection in Washtenaw County. In a statement yesterday, county health officials issued an alert about a local case and warned of potential exposure at Trinity Health Ann Arbor Emergency Department on March 1.

The other new case is in Wayne County. In a March 3 news release, the county health department said the patient is an adult thought to have contracted the virus during international travel. Officials warned of potential exposures at a pharmacy and different medical clinics in Dearborn on February 27 and February 29.

Wayne County Public Health said the recent cases in Michigan aren't epidemiologically linked.

BA.2.87.1 COVID variant detected in Southeast Asia

News brief

Scientists examining SARS-CoV-2 wastewater samples in Southeast Asia have detected a few samples containing the BA.2.87.1 variant, the first known detection outside of South Africa.

blue purple SARS-CoV-2
NIAID/Flickr cc

In a post on X (formerly Twitter), Leshan Wannigama, MD, PhD, a clinical microbiologist and infectious disease specialist in the department of infectious diseases and infection control at Japan's Yamagata Prefectural Central Hospital, said the team found a "handful" of samples and that transmission seems to be very low.

He added that the variant was found in samples from the last week of December 2023 and the second week of January 2024.

South African scientists identified a small number of BA.2.87.1 sequences in samples collected from September to December, while noting the virus wasn't causing an increase in cases. The virus is distinct from other circulating variants and has 100 mutations when compared to the BA.2 parent lineage and contains changes that could prompt an antigenic shift.

Agencies monitoring developments

In mid February, the Centers for Disease Control and Prevention (CDC) said it is closely monitoring BA.2.87.1 because it has more than 30 changes in the spike protein compared to XBB.1.5, the variant covered by the current monovalent (single-strain) vaccines.

The CDC said viruses with multiple spike protein changes could increase the potential for immune escape from earlier infection or vaccination. It emphasized that experience with BA.2.86 and its JN.1 offshoot serves as a reminder that variant transmissibility can change quickly over time.

The European Centre for Disease Prevention and Control has also designated BA.2.87.1 as a variant under monitoring.

Yet another study shows little benefit for ivermectin with COVID-19

News brief
ivermectin pills
Diverse Stock Photos / Flickr cc

A new randomized control trial from the United Kingdom shows that using ivermectin during COVID-19 infections provided little improvement in recovery rates in patients treated in clinics. The study appeared in the Journal of Infection.

The anti-parasitic drug has been investigated since 2020 as a potential treatment for COVID-19. Some early trials suggested the drug was able to reduce mortality rates and improve outcomes, but several of them had serious flaws, the authors noted. Subsequent trials and systematic reviews have largely disproved those earlier results.

The present, open-arm study compared outcomes among 8,811 SARS-CoV-2–positive participants (median symptom duration, 5 days), who were randomized to outpatient treatment with ivermectin (2,157), standard care (3,256), and other treatments (3,398) from June 23, 2021, to July 1, 2022. All participants were followed up for 28 days.

Slight increase in well-being at 6 months

The observed median time to first recovery was 14 days in the ivermectin group and 15 in the usual-care group. The authors said this result was statistically significant (hazard ratio 1.14; 95% confidence interval [CI], 1.07 to 1.23), but the estimated hazard ratio was less than the pre-specified meaningful effect of 1.2.

Ivermectin also did not reduce the number of hospitalizations. Use of the drug, however, was associated with a slight increase in the proportion of participants feeling fully recovered at 3, 6 and 12 months. At 6 months, 74% of respondents in the ivermectin group and 71% in the usual care group reported feeling fully recovered from the original COVID-19 illness (rate ratio 1.05; 95% CI, 1.02 to 1.08).

Overall, these findings, while evidencing a small benefit in symptom duration, do not support the use of ivermectin as treatment for COVID-19.

"Overall, these findings, while evidencing a small benefit in symptom duration, do not support the use of ivermectin as treatment for COVID-19 in the community among a largely vaccinated population at the dose and duration we used," the authors wrote.

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