No reduced fertility with COVID vaccines, but infection ups risk in men
A cohort study of more than 2,000 US and Canadian women indicates that COVID-19 vaccination does not impair fertility—but men who become infected with SARS-CoV-2 may experience short-term reduced fertility, according to surveys of the women's partners.
In the study, published yesterday in the American Journal of Epidemiology, Boston University (BU) researchers analyzed survey data on COVID-19 vaccination and infection, and fertility, among female and male participants in the Pregnancy Study Online (PRESTO), an ongoing study funded by the National Institutes of Health that enrolls women trying to conceive and follows them from before conception through 6 months after delivery. Participants included 2,126 women in the United States and Canada who provided information on themselves and their male partners from December 2020 to September 2021.
The investigators conducted follow-up through November 2021.
The researchers calculated the per–menstrual cycle probability of conception using self-reported dates of participants' last period, typical menstrual cycle length, and pregnancy status. They found that the fertility rates among female participants who received at least one dose of a COVID vaccine were nearly identical to unvaccinated female participants. Fertility was likewise similar for male partners who had received at least one dose of a COVID vaccine compared with unvaccinated peers.
In contrast, men who tested positive for COVID-19 within 60 days of a given cycle had reduced fertility compared with men who never tested positive or with men who tested positive at least 60 days prior. This finding did not hold true for the women and supports previous research that has linked COVID-19 infection in men with poor sperm quality and other reproductive dysfunction, according to a BU School of Medicine news release.
First author Amelia Wesselink, PhD, MPH, said in the release, "Our study shows for the first time that COVID-19 vaccination in either partner is unrelated to fertility among couples trying to conceive through intercourse. Time-to-pregnancy was very similar regardless of vaccination status."
Senior author Lauren Wise, ScD, said, "The prospective study design, large sample size, and geographically heterogeneous study population are study strengths, as was our control for many variables such as age, socioeconomic status, preexisting health conditions, occupation, and stress levels."
Jan 20 Am J Epidemiol study
Jan 20 BU School of Medicine news release
Moderna vaccine outperforms Pfizer against Delta breakthrough cases
A study yesterday in JAMA shows the Moderna mRNA vaccine was more protective than the Pfizer-BioNTech mRNA vaccine at preventing breakthrough COVID-19 cases during the US Delta surge.
The study was based on electronic health records from 637,000 fully vaccinated patients from 63 healthcare organizations across the United States, dated from July to November 2021. Full vaccination was considered to be 2 or more weeks since a second dose of mRNA vaccine. Patients who were boosted (given a third dose) or who had prior COVID-19 infections were excluded from the study.
Moderna recipients were less likely to be infected with breakthrough cases and less likely to be hospitalized. There were 2.8 breakthrough cases per 1,000 people in those vaccinated with Pfizer and 1.6 cases per 1,000 with Moderna in November 2021, and the 60-day hospitalization rate was 13.3% for Pfizer recipients and 12.7% for Moderna.
Neither group had high mortality rates: The 60-day mortality was 1.14% (35/3,078) and 1.10% (207/18,737) for Moderna and Pfizer recipients, respectively.
"Although there is a difference in breakthrough infections, both vaccines are highly protective against SARS-COV2 infection and especially against the most severe consequences of infection," said study coauthor Pamela B. Davis MD, PhD, in a Case Western University press release.
Jan 20 JAMA study
Jan 20 Case Western University press release
US flu levels drop slightly for second consecutive week
For the second week in a row, US flu markers showed a slight decline, though activity is still elevated and will likely continue for several more weeks, the US Centers for Disease Prevention and Control (CDC) said today in its weekly update.
The percentage of outpatient visits for flulike illness is still above the national baseline, but it dropped from 4.3% to 3.5% last week. The CDC has said that flu is just one of multiple respiratory viruses contributing to flulike illness levels and that flu levels vary in different parts of the country.
The number of states reporting high or very high flu activity, another indicator of clinic visits for flu, dropped from 21 to 14 last week. Hospitalizations declined, and the percentage of respiratory specimens that tested positive for flu at clinical labs dropped from 2.2% to 1.8%.
Two more pediatric flu deaths were reported, bringing the season's total to five. Both occurred during the week ending Jan 15. One involved the H3N2 strain, and the other was from an unsubtyped influenza A strain.
Very little influenza B was detected, and, of influenza A strains, H3N2 is still overwhelmingly dominant, making up 100% of subtyped samples at public health labs. Most H3N2 viruses are genetically related to the vaccine virus; however, the CDC said it is seeing some antigenic differences as the virus continues to evolve.
Jan 21 CDC FluView report
Nigeria reports more vaccine-derived polio cases
Nigeria is the only country that reported new polio cases this week, part of ongoing circulating vaccine-derived poliovirus type 2 (cVDPV2) activity in a number of African countries, the Global Polio Eradication Initiative (GPEI) said in its latest weekly update.
All 3 cases are included in the country's total for 2021, which now stands at 388. The new cases are in Kano, Katsina, and Borno states.
The WHO declared polio a public health emergency of international concern in May of 2014. Since then, wild poliovirus cases have dropped sharply, but a number of countries are still reporting vaccine-derived polio cases.
At the WHO's last polio emergency committee meeting, the group said some of its top concerns are cross-border spread of vaccine-derived polio and the unpredictable wild poliovirus type 1 situation in Afghanistan.
Jan 20 GPEI update
Nov 24, 2021, CIDRAP News scan