key: cord-0906485-80be4uf4
authors: Usmanova, Nazokat; Hipp, Heather S.
title: Reassuring Transfer Outcomes Following COVID-19 Vaccination
date: 2022-01-31
journal: Fertil Steril
DOI: 10.1016/j.fertnstert.2022.01.032
sha: 6fe737d1692e9fb6b66b0f819b48a9b48281b118
doc_id: 906485
cord_uid: 80be4uf4

nan

The coronavirus (COVID-19) pandemic has brought significant morbidity and mortality to millions of individuals over the last two years. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) impacts the respiratory and cardiovascular systems most acutely, but its potential effects on other organ systems cannot be ignored. While studies show an increased risk of severe obstetric morbidity and mortality associated with the COVID-19 infection during pregnancy (1, 2) , there is also increasing attention on the effect of an infection or vaccine on the reproductive tract and, more specifically, fertility outcomes.

In vitro studies have hypothesized that the SARS-CoV-2 infection is not likely to have an effect on endometrial function (3), and there is not current evidence of infection of gametes or embryos by the virus (2) . Clinical studies on the specific impacts of the SARS-CoV-2 virus and its vaccine on fertility and Assisted Reproductive Technology (ART) outcomes are just emerging, however. Orvieto, et al. compared cycle outcomes in 36 couples before and after vaccination with the BNT162b2 (Pfizer) vaccine, finding no differences in cycle outcomes, including semen parameters and number of mature oocytes and top-quality embryos (4) . In this issue, the same group of researchers have expanded their prior study in both size and scope to examine the effects of both COVID-19 infection and vaccination on transfer outcomes in frozen embryo transfer cycles (5) . In this single center, retrospective cohort study, Dr. Aizer and colleagues included 428 patients who underwent 672 FET cycles. They compared outcomes among four groups of patients: 1) 26 patients with immunity from an infection 2) 115 patients who received COVID-19 vaccination 3) 93 patients with no immunity who received treatment in the same study period in 2021 and 4) 194 patients without immunity who received treatment in 2019 prior to the pandemic. They found no differences in evaluated outcomes between any of the groups including, most importantly, ongoing pregnancy rate per transfer. Given its limited study time frame, live birth rate was not yet reported but would be an important follow up from this study.

The article comes at a critical time. Vaccine hesitancy, especially among women planning pregnancy or currently pregnant, has hampered government and health organization efforts to increase population-wide vaccine uptake. Although this is a relatively small study (220 transfers in 115 vaccinated patients), it is one of the first published reports of transfer outcomes in the ART population following vaccination. It is reassuring news to see no effect of the vaccine on pregnancy rates. The authors are in Israel, one of the first countries to have widespread vaccination, and they are to be commended for collating their data expeditiously for publication.

There are a few limitations to be considered, however, beyond the sample size. First, the patients were quite young with a mean age ~ 31 years, limiting the generalizability of the study to older patient populations. There was also heterogeneity in embryo stage at transfer. Approximately 50-60% of the transfers were of cleavage stage embryos and none of the embryos underwent pre-implantation genetic testing (PGT), which may limit generalizability in countries and clinics in which blastocyst stage transfer and PGT are more common. The last variable of note is the longer time to FET post-infection versus post-vaccination, which likely occurred naturally as vaccine availability slowly increased over time. There may be an effect of an acute or subacute versus resolved COVID-19 infection on IVF outcomes. They had a small number of patients with immunity attained through infection and did not include data regarding the severity of the infection. With increasing awareness of post-COVID conditions (aka long COVID) and continued infection waves worldwide, it will be interesting to see future studies of ART treatment outcomes in patients who have had COVID-19.

Update: Characteristics of Symptomatic Women of Reproductive Age with Laboratory-Confirmed SARS-CoV-2 Infection by Pregnancy Status -United States

ASRM patient management and clinical recommendations during the CORONAVIRUS (COVID-19) pandemic Update No. 10

SARS-CoV-2 infection risk assessment in the endometrium: viral infection-related gene expression across the menstrual cycle

Does mRNA SARS-CoV-2 vaccine influence patients' performance during IVF-ET cycle?

The effect of COVID-19 immunity on frozen-thawed embryo transfer cycles outcome

J o u r n a l P r e -p r o o f Despite these limitations, Aizer and colleagues present novel findings at a crucial time to help the reproductive community in patient counseling. The findings add support to the recommendations of major health organizations, including the Centers for Disease Control and Prevention, the American Society of Reproductive Medicine, and American College of Obstetricians and Gynecologists, for vaccination against COVID-19 for patients seeking fertility.J o u r n a l P r e -p r o o f