Investigating trends in those who experience menstrual bleeding changes after SARS-CoV-2 vaccination

The prevalence of menstrual changes in COVID-19 vaccinated women: A cross-sectional study

Background

This study aimed to examine the prevalence of menstrual cycle changes (MCs) and their patterns among healthy Syrian women following the administration of the first and second doses of a vaccine.

Methods

A cross-sectional online survey following campaigns for COVID-19 vaccines was conducted in 2022 from June 26 to August 3. Data collected included the participants' demographic characteristics, vaccination status, and multiple-choice questions for MCs changes after the first and second doses.

Results

Of 236, 89.8 % completed all shots of the vaccine. After the first dose, 36.9 % reported MCs, and 35 % after the second dose. Most women did not experience changes in menstrual cycle frequency-81.8 % after the first dose and 83.4 % after the second dose. Similarly, most women did not observe changes in cycle length, or menstrual flow quantity-5.5 % after the first dose and 8 % after the second dose reported spotting. Dysmenorrhea was reported by 15.7 % and 14.1 % of women after the first and second doses, respectively.

Conclusion

MCs are a potential symptom that a healthy woman at childbearing age could have after a different type of COVID-19 vaccine. MCs patterns do not significantly differ following vaccine doses.

Physiological Response to the COVID-19 Vaccine: Insights From a Prospective, Randomized, Single-Blinded, Crossover Trial

BACKGROUND

Rapid development and implementation of vaccines constituted a crucial step in containing the COVID-19 pandemic. A comprehensive understanding of physiological responses to these vaccines is important to build trust in medicine.

OBJECTIVE

This study aims to investigate temporal dynamics before and after COVID-19 vaccination in 4 physiological parameters as well as the duration of menstrual cycle phases.

METHODS

In a prospective trial, 17,825 adults in the Netherlands wore a medical device on their wrist for up to 9 months. The device recorded their physiological signals and synchronized with a complementary smartphone app. By means of multilevel quadratic regression, we examined changes in wearable-recorded breathing rate, wrist skin temperature, heart rate, heart rate variability, and objectively assessed the duration of menstrual cycle phases in menstruating participants to assess the effects of COVID-19 vaccination.

RESULTS

The recorded physiological signals demonstrated short-term increases in breathing rate and heart rate after COVID-19 vaccination followed by a prompt rebound to baseline levels likely reflecting biological mechanisms accompanying the immune response to vaccination. No sex differences were evident in the measured physiological responses. In menstruating participants, we found a 0.8% decrease in the duration of the menstrual phase following vaccination.

CONCLUSIONS

The observed short-term changes suggest that COVID-19 vaccines are not associated with long-term biophysical issues. Taken together, our work provides valuable insights into continuous fluctuations of physiological responses to vaccination and highlights the importance of digital solutions in health care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s13063-021-05241-5.

Measurement of changes to the menstrual cycle: A transdisciplinary systematic review evaluating measure quality and utility for clinical trials

Despite the importance of menstruation and the menstrual cycle to health, human rights, and sociocultural and economic wellbeing, the study of menstrual health suffers from a lack of funding, and research remains fractured across many disciplines. We sought to systematically review validated approaches to measure four aspects of changes to the menstrual cycle-bleeding, blood, pain, and perceptions-caused by any source and used within any field. We then evaluated the measure quality and utility for clinical trials of the identified instruments. We searched MEDLINE, Embase, and four instrument databases and included peer-reviewed articles published between 2006 and 2023 that reported on the development or validation of instruments assessing menstrual changes using quantitative or mixed-methods methodology. From a total of 8,490 articles, 8,316 were excluded, yielding 174 articles reporting on 94 instruments. Almost half of articles were from the United States or United Kingdom and over half of instruments were only in English, Spanish, French, or Portuguese. Most instruments measured bleeding parameters, uterine pain, or perceptions, but few assessed characteristics of blood. Nearly 60% of instruments were developed for populations with menstrual or gynecologic disorders or symptoms. Most instruments had fair or good measure quality or clinical trial utility; however, most instruments lacked evidence on responsiveness, question sensitivity and/or transferability, and only three instruments had good scores of both quality and utility. Although we took a novel, transdisciplinary approach, our systematic review found important gaps in the literature and instrument landscape, pointing towards a need to examine the menstrual cycle in a more comprehensive, inclusive, and standardized way. Our findings can inform the development of new or modified instruments, which-if used across the many fields that study menstrual health and within clinical trials-can contribute to a more systemic and holistic understanding of menstruation and the menstrual cycle.

Association between COVID-19 vaccination and menstruation: a state of the science review

INTRODUCTION

Menstrual health is a key patient-reported outcome beyond its importance as a general indicator of health and fertility. However, menstrual function was not measured in the clinical trials of COVID-19 vaccines. The purpose of this review was to synthesise the existing literature on the relationship between COVID-19 vaccination and menstrual health outcomes.

METHODS

A PubMed search to 31 October 2023 identified a total of 53 publications: 11 prospective cohort studies, 11 retrospective cohort studies or registry-based cohort studies, and 31 cross-sectional or retrospective case-control studies.

RESULTS

Identified studies were generally at moderate-to-high risk of bias due to retrospective design, interviewer bias, and failure to include a non-vaccinated control group. Nonetheless, the bulk of the literature demonstrates that COVID-19 vaccine is associated with temporary changes in menstrual characteristics (cycle length and flow) and menstrual pain. Follicular phase (at the time of vaccination) is associated with greater increases in cycle length. Evidence suggests temporary post-vaccine menstrual changes in adolescents, abnormal vaginal bleeding in postmenopausal individuals, and a potential protective effect of using hormonal contraception.

CONCLUSIONS

In this review we found evidence supporting an association between the COVID-19 vaccine and menstrual health outcomes. Given the importance of menstrual function to overall health, we recommend that all future vaccine trials include menstruation as a study outcome. Future vaccine studies should include rigorous assessment of the menstrual cycle as an outcome variable to limit sources of bias, identify biological mechanisms, and elucidate the impact of stress.

The direct effect of SARS-CoV-2 virus vaccination on human ovarian granulosa cells explains menstrual irregularities

Following administration of the SARS-CoV-2 vaccine, many women worldwide reported short-term menstrual irregularities. Although menstrual bleeding, "the fifth vital sign", is experienced by more than 300 million people on any given day worldwide, these changes were only partially studied. Irregular periods are important well beyond fertility and the discomfort they impose; they are associated with the risk of cardiovascular morbidity, chronic diseases, and premature mortality. Pre-clinical examination of the vaccine polymeric envelope indicates its accumulation in the ovaries. The somatic endocrine cells of the ovarian follicle - the granulosa cells (GCs)-participate in the strict hypothalamic-pituitary-ovarian (HPO) feedback loop that governs the menstrual cycle via endocrine and paracrine regulators, as AMH and Inhibins. We aimed to unravel the direct effect of the COVID-19 vaccine on GCs and link their post-vaccine activity to changes in menstrual patterns. Human primary GCs exposed in-vitro to the Pfizer COVID-19 vaccine BNT162b2, demonstrated no change in their viability but altered mRNA transcripts, specifically of the regulatory key factors: InhibinB was upregulated, whereas AMH was downregulated. We further examined pre- and post-vaccination blood samples from individual women and found a 2-3 folds change in the post-vaccination FSH/InhibinB protein level ratio, compared to their pre-vaccination values. This altered expression of InhibinB could significantly impact the HPO axis in vaccinated women and may ultimately influence the endometrium cyclicity, manifested clinically by the commonly reported changes in menstrual bleeding patterns.

Menstrual Cycle Disturbances after COVID-19 Vaccination: A Cross-Sectional Study

BACKGROUND

Following COVID-19 vaccination, some women suffered from menstrual cycle disturbances. This study aimed to investigate menstrual cycle disturbances after COVID-19 vaccination in women of reproductive age.

MATERIALS AND METHODS

This cross-sectional study was performed on 407 vaccinated women in the vaccination center of Imam Hossein Hospital (Tehran, Iran) between October 2021 and October 2022. They were interviewed based on a research-made checklist which consisted of two areas of questions about the baseline characteristics of participants and menstrual cycle characteristics to explore menstrual characteristics following COVID-19 vaccination.

RESULTS

The prevalence of menstrual disturbances was higher after the third dose (38.3%) compared with the second (27.9%) and first (17.7%) doses (P<0.001). After the first dose, a history of polycystic ovarian syndrome [PCOS, odds ratio (OR)=7.35, 95% confidential interval (CI)= (3.64-14.82), P<0.001] and menstrual disturbances with unknown etiology [OR=15.23, 95% CI=(6.30-36.80), P<0.001] could predict menstrual disturbances. After the second dose, a history of menstrual disturbances with unknown etiology [OR=3.83, 95% CI=(1.47-9.94), P=0.006] and menstrual disturbances after the first dose [OR=201.96, 95% CI= (40.99-994.90), P<0.001] were predictors of menstrual disturbances. After the third dose, a history of menstrual disturbances with unknown etiology [OR=3.09, 95% CI= (1.00-9.52), P=0.048], menstrual disturbances after the first [OR=9.82, 95% CI=(1.38-69.69), P=0.022] and second [OR=7.83, 95% CI=(1.46-41.92), P=0.016] doses could predict menstrual disturbances.

CONCLUSION

We detected that many women experienced various menstrual disturbances after vaccination against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Furthermore, a history of menstrual abnormalities (before COVID-19 vaccination and following the previous doses of these vaccines) was associated with developing menstrual disturbances.

COVID-19 (SARS-CoV-2) mRNA vaccination does not affect basal sex hormone levels (follicle-stimulating hormone, luteinizing hormone, estradiol) in reproductive-age women

OBJECTIVE

People vaccinated with the coronavirus disease 2019 (COVID-19) (severe acute respiratory syndrome coronavirus-2 [SARS-CoV-2]) mRNA vaccine have reported experiencing various adverse effects. For instance, reproductive-age women have presented with complaints of abnormal uterine bleeding or menstrual cycle changes. We speculated that differences in basal sex hormone levels before and after vaccination may be present in women who experienced irregular bleeding or menstrual cycle changes; thus, this study aimed to investigate the differences in basal sex hormone levels of women before and after two doses of SARS-CoV-2 mRNA vaccination.

METHODS

This retrospective study included patients who received SARS-CoV-2 mRNA vaccines between January 2021 and February 2022 at a single center. In an outpatient setting, patients were queried regarding their menstrual cycle, the date of SARS-CoV-2 mRNA vaccination, vaccination type, and vaccination side effects. Differences in basal hormone levels (menstrual cycle days 2-3, follicle-stimulating hormone [FSH], luteinizing hormone [LH], and estradiol) before and after vaccination were compared.

RESULTS

Among the 326 patients, patients with no laboratory records of the hormones were excluded. The median time interval between SARS-CoV-2 mRNA vaccination and the laboratory test day was 79 days (interquartile range, 44 to 127). A comparative analysis of these hormones before and after vaccination revealed no significant differences. Subgroup analyses based on age and reported adverse events also found no statistically significant differences.

CONCLUSION

This study showed no significant differences in basal hormone levels (FSH, LH, and estradiol) before and after SARS-CoV-2 mRNA vaccination.

Association of heavy menstrual bleeding with cardiovascular disease in US female hospitalizations

BACKGROUND

Heavy menstrual bleeding (HMB) is a common menstrual disorder associated with multiple risk factors of cardiovascular disease (CVD) in women. In addition, HMB is often present with irregular menstruation (IM) which is a risk factor for CVD outcomes. However, the relationship between HMB and CVD outcomes is unexplored in the presence or absence of IM. We determined the association of HMB with multiple CVD outcomes using a nationally representative sample of female hospitalizations in the US.

METHODS

All hospitalizations of females with HMB diagnosis and normal menstrual cycles from ages of 18 to 70 years were extracted from the National Inpatient Sample Database, 2017. The HMB was defined using the International Classification of Diseases (ICD)-10 for excessive and frequent menstruation bleeding and included any current or history of HMB diagnosis. Outcomes including major adverse cardiovascular events (MACE), coronary heart disease (CHD), stroke, heart failure (HF), atrial fibrillation (AF) or arrhythmia, myocardial infarction (MI), and diabetes (DM) were defined using ICD-10 codes. Adjusted logistic regression and prosperity scores-matched logistic regression analyses were conducted to summarize adjusted associations with an odds ratio (OR) and a 95% confidence interval (CI).

RESULTS

Among 2,430,851 hospitalizations, HMB was observed in 7762 (0.68%) females with age ≤ 40 years and 11,164 (0.86%) females with age > 40 years. Among hospitalizations with age ≤ 40 years, HMB was significantly associated with increased odds of CVD outcomes including MACE (OR = 1.61; 95% CI: 1.25, 2.08), CHD (OR = 1.72; 95% CI: 1.10, 2.71), stroke (OR = 1.95; 95% CI: 1.12, 3.40), HF (OR = 1.53; 95% CI: 1.15, 2.03), and AF/arrhythmia (OR = 1.84; 95% CI: 1.34, 2.54). These associations were confirmed in multiple sensitivity analyses. In contrast, HMB was not robustly associated with CVD events among hospitalizations of women with age > 40 years. HMB without IM was strongly associated with DM, HF, AF, and MACE outcomes while HMB with IM was strongly associated with CHD and AF outcomes in hospitalizations of young women.

CONCLUSIONS

HMB is associated with CVD events among US hospitalizations of young women. A routine investigation and screening of menstrual disorders, especially HMB, is useful for CVD risk stratification and management in young women.

Abnormal uterine bleeding diagnoses and care following COVID-19 vaccination

BACKGROUND

There is evidence suggesting that COVID-19 vaccination may be associated with small, transitory effects on uterine bleeding, possibly including menstrual timing, flow, and duration, in some individuals. However, changes in health care seeking, diagnosis, and workup for abnormal uterine bleeding in the COVID-19 vaccine era are less clear.

OBJECTIVE

This study aimed to assess the impact of COVID-19 vaccination on incident abnormal uterine bleeding diagnosis and diagnostic evaluation in a large integrated health system.

STUDY DESIGN

Using segmented regression, we assessed whether the availability of COVID-19 vaccines was associated with changes in monthly, population-based rates of incident abnormal uterine bleeding diagnoses relative to the prepandemic period in health system members aged 16 to 44 years who were not menopausal. We also compared clinical and demographic characteristics of patients diagnosed with incident abnormal uterine bleeding between December 2020 and October 13, 2021 by vaccination status (never vaccinated, vaccinated in the 60 days before diagnosis, vaccinated >60 days before diagnosis). Furthermore, we conducted detailed chart review of patients diagnosed with abnormal uterine bleeding within 1 to 60 days of COVID-19 vaccination in the same time period.

RESULTS

In monthly populations ranging from 79,000 to 85,000 female health system members, incidence of abnormal uterine bleeding diagnosis per 100,000 person-days ranged from 8.97 to 19.19. There was no significant change in the level or trend in the incidence of abnormal uterine bleeding diagnoses between the prepandemic (January 2019-January 2020) and post-COVID-19 vaccine (December 2020-December 2021) periods. A comparison of clinical characteristics of 2717 abnormal uterine bleeding cases by vaccination status suggested that abnormal bleeding among recently vaccinated patients was similar or less severe than abnormal bleeding among patients who had never been vaccinated or those vaccinated >60 days before. There were also significant differences in age and race of patients with incident abnormal uterine bleeding diagnoses by vaccination status (Ps<.02). Never-vaccinated patients were the youngest and those vaccinated >60 days before were the oldest. The proportion of patients who were Black/African American was highest among never-vaccinated patients, and the proportion of Asian patients was higher among vaccinated patients. Chart review of 114 confirmed postvaccination abnormal uterine bleeding cases diagnosed from December 2020 through October 13, 2021 found that the most common symptoms reported were changes in timing, duration, and volume of bleeding. Approximately one-third of cases received no diagnostic workup; 57% had no etiology for the bleeding documented in the electronic health record. In 12% of cases, the patient mentioned or asked about a possible link between their bleeding and their recent COVID-19 vaccine.

CONCLUSION

The availability of COVID-19 vaccination was not associated with a change in incidence of medically attended abnormal uterine bleeding in our population of over 79,000 female patients of reproductive age. In addition, among 2717 patients with abnormal uterine bleeding diagnoses in the period following COVID-19 vaccine availability, receipt of the vaccine was not associated with greater bleeding severity.

Impact of COVID-19 infections and vaccination on menstrual cycle symptoms in the south of Jordan: a cross-sectional study

BACKGROUND

Several recent studies have highlighted the need for more evaluation of the impact of COVID-19 infections and vaccines on the reproductive system and menstruation. This study aimed to assess the impact of COVID-19 infection and vaccines on menstrual symptoms.

METHODS

A cross-sectional survey utilizing face-to-face interviews from January 1 to 31 March 2022 was conducted in the city of Al-Karak in southern Jordan. The questionnaire included sociodemographic characteristics, medical and reproductive history, the contraceptive method used if any, menstrual cycle (MC) status, previous medical and drug history, and the impact of infection and vaccination on the MC.

RESULTS

The study questionnaire was completed by 400 participants with a mean age of 32.1±12.6 years. Regarding the history of COVID-19 infections, 33.8% of the participants reported a history of confirmed COVID-19 infections, 77.8% of them did not report any menstrual changes following the infection, while the remaining 22.2% reported changes in menstruation. The most commonly reported post-COVID-19 manifestations were irregular (27.6%) and light menstrual cycle (MC) (24.15) or dysmenorrhea (24.1%). Heavy menstruation was reported by 17.2% of participants post-COVID-19 infection. Two-thirds of the study participants (66.6%) reported no changes in the MC following the administration of the COVID-19 vaccine. The most reported symptoms for those who experienced changes in the MC following the vaccination were irregular cycle (13.1%), heavy menstruation (7%), and light menstruation (7%). Other reported symptoms were dysmenorrhea (4.6%), intermenstrual bleeding (1.2%), and amenorrhea (0.5%).

CONCLUSION

This study revealed minor changes in the MC following COVID-19 infections and administration of the COVID-19 vaccine. These findings are consistent with published reports. It is recommended that future clinical trials for new vaccines for women of childbearing age include outcomes related to sex hormones and MC. Women should be encouraged to take the vaccines and report symptoms to healthcare professionals for further assessment.

Handicraft art leisure activities and cognitive reserve

ObjectiveOlder individuals face a higher likelihood of developing dementia. The rate of cognitive decline resulting from dementia is not equivalent for all, as some patients with dementia are able to function independently longer than others, despite having similar disease burden. The cognitive reserve (CR) theory provides one explanation for the differing rate of decline. CR suggests that there are factors-most notably, educational attainment and occupational attainment-that can protect against the cognitive decline. Although the beneficial effects of these notable CR factors are clear, not all are easily modifiable. Participation in leisure activities may represent a more easily modifiable factor. Some research hints at beneficial effects of leisure activities, although specific leisure activities have not been well examined. The present study examined the relations between handicraft art leisure activities (HALAs) and multiple cognitive domains. MethodArchival WAIS-IV and demographic data for 50 California retirement community residents were examined. ResultsHALA participation accounted for statistically significant variance in working memory performance (R2 = .40, β = .24%) over and above the established CR factors of age, depression, educational attainment, and occupational attainment. In addition, HALA participation was related to a better ability to perform abstract visual information tasks (Block Design subtest, r = .28, p = .05) and non-verbal reasoning tasks (Visual Puzzles subtest, r = .38, p = .008). ConclusionsHALA participation among older adults could contribute to the retention of cognitive function, supporting the role of HALA participation as a CR factor.

Timing of Coronavirus Disease 2019 (COVID-19) Vaccination and Effects on Menstrual Cycle Changes

OBJECTIVE

To assess whether menstrual cycle timing (follicular or luteal phase) of coronavirus disease 2019 (COVID-19) vaccine administration is associated with cycle length changes.

METHODS

We used prospectively collected (2021-2022) menstrual cycle tracking data from 19,497 reproductive-aged users of the application "Natural Cycles." We identified whether vaccine was delivered in the follicular or luteal phase and also included an unvaccinated control group. Our primary outcome was the adjusted within-individual change in cycle length (in days) from the average of the three menstrual cycles before the first vaccination cycle (individuals in the unvaccinated control group were assigned a notional vaccine date). We also assessed cycle length changes in the second vaccination cycle and whether a clinically significant change in cycle length (8 days or more) occurred in either cycle.

RESULTS

Most individuals were younger than age 35 years (80.1%) and from North America (28.6%), continental Europe (33.5%), or the United Kingdom (31.7%). In the vaccinated group, the majority received an mRNA vaccine (63.8% of the full sample). Individuals vaccinated in the follicular phase experienced an average 1-day longer adjusted cycle length with a first or second dose of COVID-19 vaccine compared with their prevaccination average (first dose: 1.00 day [98.75% CI, 0.88-1.13], second dose: 1.11 days [98.75% CI, 0.93-1.29]); those vaccinated in the luteal phase and those in the unvaccinated control group experienced no change in cycle length (respectively, first dose: -0.09 days [98.75% CI, -0.26 to 0.07], second dose: 0.06 days [98.75% CI, -0.16 to 0.29], unvaccinated notional first dose: 0.08 days [98.75% CI, -0.10 to 0.27], second dose: 0.17 days [98.75% CI, -0.04 to 0.38]). Those vaccinated during the follicular phase were also more likely to experience a clinically significant change in cycle length (8 days or more; first dose: 6.8%) than those vaccinated in the luteal phase or unvaccinated (3.3% and 5.0%, respectively; P <.001).

CONCLUSION

COVID-19 vaccine-related cycle length increases are associated with receipt of vaccination in the first half of the menstrual cycle (follicular phase).

COVID-19 and abnormal uterine bleeding: potential associations and mechanisms

The impact of COVID-19 on menstruation has received a high level of public and media interest. Despite this, uncertainty exists about the advice that women and people who menstruate should receive in relation to the expected impact of SARS-CoV-2 infection, long COVID or COVID-19 vaccination on menstruation. Furthermore, the mechanisms leading to these reported menstrual changes are poorly understood. This review evaluates the published literature on COVID-19 and its impact on menstrual bleeding, discussing the strengths and limitations of these studies. We present evidence consistent with SARS-CoV-2 infection and long COVID having an association with changes in menstrual bleeding parameters and that the impact of COVID vaccination on menstruation appears less significant. An overview of menstrual physiology and known causes of abnormal uterine bleeding (AUB) is provided before discussing potential mechanisms which may underpin the menstrual disturbance reported with COVID-19, highlighting areas for future scientific study. Finally, consideration is given to the effect that menstruation may have on COVID-19, including the impact of the ovarian sex hormones on acute COVID-19 severity and susceptibility and reported variation in long COVID symptoms across the menstrual cycle. Understanding the current evidence and addressing gaps in our knowledge in this area are essential to inform public health policy, direct the treatment of menstrual disturbance and facilitate development of new therapies, which may reduce the severity of COVID-19 and improve quality of life for those experiencing long COVID.

Association between COVID-19 and vaccination on menstrual cycle

OBJECTIVE

To evaluate changes in the menstrual pattern of women of reproductive age infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or vaccinated against coronavirus disease 2019 (COVID-19).

METHODS

A cross-sectional study at the University of Campinas, Brazil using Google questionnaire applied from December 2021 through February 2022, disseminated through snowball technique. Participants responded about characteristics of their menstrual cycle before the pandemic and before COVID-19 vaccination, and then about characteristics of their cycle 3 months after infection with SARS-CoV-2 and 3 months after vaccination. Our primary outcome was a binary indicator of changes in the menstrual cycle. We used multivariate regression analysis to identify factors associated with menstrual changes.

RESULTS

We received 1012 completed questionnaires and 735 (72.7%) were from women aged between 20 and 39 years, 745 (73.6%) were White and 491 (48.6%) lived with a partner. A total of 419 (41.6%) of the women reported SARS-CoV-2 infection; however, only two of them were hospitalized, and 995 (98.8%) of women had at least one dose of COVID-19 vaccine. About menstrual characteristics, 170 (41.3%) reported changes after having COVID-19 and 294 (29.9%) after COVID-19 vaccination, respectively. Few years of schooling, lower income, and non-white ethnicity were related to higher reports of menstrual changes after COVID-19. Menstrual changes after COVID-19 vaccination were associated with not using contraception. Higher body mass index was associated with irregularities in cyclicity and bleeding days, after COVID-19 and COVID-19 vaccination, respectively.

CONCLUSION

Our results corroborated the stability of the menstrual cycle after having COVID-19 or COVID-19 vaccination; however, there is a potential relationship between menstrual changes and socioeconomic factors as well as contraceptive use.

Prolongation of the Menstrual Cycle After Receipt of the Primary Series and Booster Doses of mRNA Coronavirus Disease 2019 (COVID-19) Vaccination

OBJECTIVE

To quantitatively evaluate the effect of a booster vaccination dose against coronavirus disease 2019 (COVID-19) on menstrual cycle in a large-scale retrospective cohort study using a menstrual cycle tracking smartphone application (app).

METHODS

Prospectively or retrospectively recorded data, including the start and finish dates of menstrual cycles, were collected with the app. Detailed data on vaccinations, side effects, and participants' characteristics were retrospectively collected from a questionnaire on the app. For each COVID-19 vaccination shot (first, second, and third), within-individual changes in menstrual cycle length up to the fourth postvaccination cycle were evaluated.

RESULTS

Among the 7,376 and 6,873 participants who had the first and second COVID-19 vaccine doses in different menstrual cycles, respectively, menstrual cycles immediately after the vaccination (first postvaccination cycles) were an average of 0.22 days (95% CI, 0.06-0.39) and 0.37 days (95% CI, 0.20-0.54) longer than the prevaccination cycle. In contrast, among the 1,672 participants who received the first and second doses in the same cycle, the first postvaccination cycle was an average of 4.21 days (95% CI, 3.69-4.72) longer. The second to fourth postvaccination cycles returned to the level of the prevaccination cycle. However, among the 4,768 participants who had the third COVID-19 vaccine dose, the menstrual cycle immediately after the vaccination was an average of 1.20 days (95% CI, 1.00-1.40) longer, with prolongation of cycles of 0.27 days (95% CI, 0.10-0.44) to 0.41 days (95% CI, 0.22-0.59) persisting from the second to the fourth postvaccination cycle.

CONCLUSION

The booster shot against COVID-19 may have a greater and longer-lasting effect on menstrual cycles than the primary-series shots. Although the effect size was small, evidence on the side effects of immunization on menstruation should be accumulated.

COVID-19 vaccine boosters for young adults: a risk benefit assessment and ethical analysis of mandate policies at universities

In 2022, students at North American universities with third-dose COVID-19 vaccine mandates risk disenrolment if unvaccinated. To assess the appropriateness of booster mandates in this age group, we combine empirical risk-benefit assessment and ethical analysis. To prevent one COVID-19 hospitalisation over a 6-month period, we estimate that 31 207-42 836 young adults aged 18-29 years must receive a third mRNA vaccine. Booster mandates in young adults are expected to cause a net harm: per COVID-19 hospitalisation prevented, we anticipate at least 18.5 serious adverse events from mRNA vaccines, including 1.5-4.6 booster-associated myopericarditis cases in males (typically requiring hospitalisation). We also anticipate 1430-4626 cases of grade ≥3 reactogenicity interfering with daily activities (although typically not requiring hospitalisation). University booster mandates are unethical because they: (1) are not based on an updated (Omicron era) stratified risk-benefit assessment for this age group; (2) may result in a net harm to healthy young adults; (3) are not proportionate: expected harms are not outweighed by public health benefits given modest and transient effectiveness of vaccines against transmission; (4) violate the reciprocity principle because serious vaccine-related harms are not reliably compensated due to gaps in vaccine injury schemes; and (5) may result in wider social harms. We consider counterarguments including efforts to increase safety on campus but find these are fraught with limitations and little scientific support. Finally, we discuss the policy relevance of our analysis for primary series COVID-19 vaccine mandates.

Prevalence of menstrual irregularities after coronavirus disease 2019 vaccination: A cross-sectional study in the Eastern Province, Saudi Arabia

BACKGROUND

Reports indicate that there are menstrual cycle disturbances following coronavirus disease 2019 (COVID-19) vaccination. The present study explored the prevalence of menstrual irregularities after COVID-19 vaccination and the association of menstrual irregularities with vaccine type, doses, immediate adverse effects, history of COVID-19 infection, and its severity.

MATERIALS AND METHODS

For this cross-sectional study, 406 women of reproductive age completed an online survey about the postvaccine changes in their menstruation (cycle duration, bleeding days, and bleeding amount), COVID-19 vaccine history (doses, type of vaccine, and immediate adverse effects), history of COVID-19 infection, and its severity. Data was analyzed using SPSS; descriptive statistics were computed and Chi-square test, and binary logistic regression analysis were performed.

RESULTS

Of the total 406 women, 45% reported postvaccine changes in their menstrual cycle. The most common menstrual change was increased dysmenorrhea (68%), followed by an increase in the length of the cycle (52%). There was a significant association between postvaccine menstrual changes and the age, marital status, and family history of menstrual irregularities. No association was observed between postvaccine menstrual changes and COVID-19 vaccine-and COVID-19 infection-related variables. As per the best-fit model of our predictors, the odds of having postvaccine menstrual changes were 0.41 times less in "single" women (confidence interval [CI] = 0.26-0.27; P < 0.001) and 1.714 times greater in women who had a "family history of menstrual irregularities" (CI = 1.092-2.690; P = 0.02), respectively.

CONCLUSION

A substantial number of women complained of postvaccine menstrual changes regardless of their age, type of COVID-19 vaccine, doses, immediate adverse effects, and COVID-19 infection history/severity. Being "single" decreased the probability, whereas having a family history of menstrual irregularities increased the probability significantly of having postvaccine menstrual changes.

Associations Among Menstrual Cycle Length, Coronavirus Disease 2019 (COVID-19), and Vaccination

OBJECTIVE

To assess whether coronavirus disease 2019 (COVID-19) is associated with menstrual cycle length changes and, if so, how that compares with those undergoing vaccination or no event (control).

METHODS

We conducted a retrospective cohort analysis in which we analyzed prospectively tracked cycle-length data from users of a period tracker application who also responded to a survey regarding COVID-19 symptoms and vaccination. We restricted our sample to users aged 16-45 years, with normal cycle lengths (24-38 days) and regular tracking behavior during the five cycles around COVID-19 symptoms or vaccination or a similar time period for those experiencing no event (control group). We calculated the within-user change in cycle length (days) from the three consecutive cycles preevent average (either vaccination, disease, or neither; cycles 1-3) to the event (cycle 4) and postevent (cycle 5) cycles. We used mixed-effects models to estimate the age- and country-adjusted difference in change in cycle length across the groups.

RESULTS

We included 6,514 users from 110 countries representing 32,570 cycles (COVID-19 symptoms: 1,450; COVID-19 vaccination: 4,643; control: 421). The COVID-19 cohort experienced a 1.45-day adjusted increase in cycle length during cycle 4 (COVID-19) compared with their three preevent cycles (95% CI 0.86-2.04). The vaccinated group experienced a 1.14-day adjusted increase in cycle length during cycle 4 (COVID-19 vaccine) compared with their preevent average (95% CI 0.60-1.69). The control group (neither vaccine nor disease) experienced a 0.68-day decrease (95% CI -1.18 to -0.19) in a similar time period. Post hoc tests showed no significant differences in the magnitude of changes between the COVID-19 and vaccination cohorts. In both cohorts, cycle length changes disappeared in the postevent cycle.

CONCLUSION

Experiencing COVID-19 is associated with a small change in cycle length similar to COVID-19 vaccination. These changes resolve quickly within the next cycle.

Postmenopausal bleeding after COVID-19 vaccination

BACKGROUND

There is a growing literature base regarding menstrual changes following COVID-19 vaccination among premenopausal people. However, relatively little is known about uterine bleeding in postmenopausal people following COVID-19 vaccination.

OBJECTIVE

This study aimed to examine trends in incident postmenopausal bleeding diagnoses over time before and after COVID-19 vaccine introduction, and to describe cases of new-onset postmenopausal bleeding after COVID-19 vaccination.

STUDY DESIGN

For postmenopausal bleeding incidence calculations, monthly population-level cohorts consisted of female Kaiser Permanente Northwest members aged ≥45 years. Those diagnosed with incident postmenopausal bleeding in the electronic medical record were included in monthly numerators. Members with preexisting postmenopausal bleeding or abnormal uterine bleeding, or who were at increased risk of bleeding due to other health conditions, were excluded from monthly calculations. We used segmented regression analysis to estimate changes in the incidence of postmenopausal bleeding diagnoses from 2018 through 2021 in Kaiser Permanente Northwest members meeting the inclusion criteria, stratified by COVID-19 vaccination status in 2021. In addition, we identified all members with ≥1 COVID-19 vaccination between December 14, 2020 and August 14, 2021, who had an incident postmenopausal bleeding diagnosis within 60 days of vaccination. COVID-19 vaccination, diagnostic procedures, and presumed bleeding etiology were assessed through chart review and described. A temporal scan statistic was run on all cases without clear bleeding etiology.

RESULTS

In a population of 75,530 to 82,693 individuals per month, there was no statistically significant difference in the rate of incident postmenopausal bleeding diagnoses before and after COVID-19 vaccine introduction (P=.59). A total of 104 individuals had incident postmenopausal bleeding diagnosed within 60 days following COVID-19 vaccination; 76% of cases (79/104) were confirmed as postvaccination postmenopausal bleeding after chart review. Median time from vaccination to bleeding onset was 21 days (range: 2-54 days). Among the 56 postmenopausal bleeding cases with a provider-attributed etiology, the common causes of bleeding were uterine or cervical lesions (50% [28/56]), hormone replacement therapy (13% [7/56]), and proliferative endometrium (13% [7/56]). Among the 23 cases without a clear etiology, there was no statistically significant clustering of postmenopausal bleeding onset following vaccination.

CONCLUSION

Within this integrated health system, introduction of COVID-19 vaccines was not associated with an increase in incident postmenopausal bleeding diagnoses. Diagnosis of postmenopausal bleeding in the 60 days following receipt of a COVID-19 vaccination was rare.

The Relationship Between Menstrual Cycle Irregularities and COVID-19 Vaccination

Background After COVID-19 vaccination, females reported irregularities and changes in their menstrual cycle. We aimed to explore the menstrual irregularities following COVID-19 vaccination in Saudi women of childbearing age. Methodology The study was a cross-sectional study conducted among women in Riyadh, Saudi Arabia, who had no history of menstrual irregularities before receiving the first dose of the COVID-19 vaccine. The participants filled out an online self-administered questionnaire via Google Form about any menstrual irregularities they experienced after receiving the COVID-19 vaccine. Results A total of 535 participants completed the survey. The study found that 41.7% (223) of women experienced menstrual changes after the first dose of the COVID-19 vaccine, increasing to 44.1% (236) after the second dose. The incidence of these changes varied between the first and second doses. For example, the incidence of changes in period duration decreased from 51.6% to 48.3% after the first and second doses, respectively. Similarly, the incidence of delayed periods decreased from 48.4% to 47.9%, while dysmenorrhea increased slightly from 30.9% to 32.2% after the two doses. The incidence of heavier menstrual flow increased from 26.9% to 30.5%, while the incidence of lighter menstrual flow decreased from 26.9% to 24.6% after the first and second doses, respectively. Conclusions There is an increased incidence of changes in menstrual cycle after COVID-19 vaccination, particularly in menstrual cycle length, menstrual pain, and the flow of menstruation. Future studies are needed to investigate the potential underlying biological mechanisms.

Impact of COVID-19 Vaccinations on Menstrual Bleeding

INTRODUCTION

Vaccination has a fundamental role in protecting against and modifying the severity of several infectious diseases, including COVID-19. Several immune and non-immune adverse events have been reported post-COVID-19 vaccine. The aim of this study was to assess the effect of the COVID-19 vaccine on women's menstrual bleeding.

METHODS

A cross-sectional study was conducted among 399 vaccinated women in the Eastern Province of Saudi Arabia. Data were collected using a direct interview-based questionnaire including four sections.

RESULTS

A total of 399 women were recruited, with a mean age of 25.54 ± 6.177 years. More than half (53.9%) of the participants reported post-vaccination menstrual bleeding abnormality in terms of a heavy or irregular cycle. Out of the total number, 40 (21.4%) women reported having heavy menstrual flow, and 67 (16.8%) had non-menstrual bleeding after receiving the COVID-19 vaccine. Fully vaccinated women were at a greater risk of post-vaccination menstrual bleeding abnormality (p = 0.058). However, there was no correlation between booster shot type and menstrual bleeding abnormality (p > 0.05). In addition, there was no significant association between non-menstrual bleeding and the type of booster shot, the type of the first dose, and prior history of COVID-19 infection (p > 0.05).

CONCLUSION

Despite vaccination being the most effective way to prevent COVID-19, it does have an impact on menstrual bleeding in terms of menorrhagia and metrorrhagia. Therefore, more studies are needed to understand the mechanism and the long-term impact of COVID-19 vaccines on the hemostatic system.

Menstrual abnormalities after COVID-19 vaccination in the Netherlands: A description of spontaneous and longitudinal patient-reported data

AIMS

During the COVID-19 vaccination campaigns, the number of reports of menstrual abnormalities increased rapidly. Here, we describe the nature and potential risk factors associated with menstrual abnormalities based on spontaneously reporting data as well as data from a prospective cohort event monitoring (CEM) study as these are poorly studied.

METHODS

Reports of menstrual abnormalities received by the Netherlands Pharmacovigilance Centre Lareb in the spontaneous reporting system between February 2021 and April 2022 were summarized. In addition, logistic regression analysis was performed on the reported menstrual abnormalities in the CEM study to assess the association between person characteristics, prior SARS-CoV-2 infection and use of hormonal contraceptives and the occurrence of menstrual abnormalities after vaccination.

RESULTS

We analysed over 24 000 spontaneous reports of menstrual abnormalities and over 500 episodes (among 16 929 included women) of menstrual abnormalities in the CEM study. The CEM study showed an incidence of 41.4 per 1000 women aged ≤54 years. Amenorrhoea/oligomenorrhoea and heavy menstrual bleeding collectively accounted for about half of all abnormalities reported. Significant associations were observed for the age group 25-34 years (odds ratio 2.18; 95% confidence interval 1.45-3.41) and the Pfizer vaccine (odds ratio 3.04; 95% confidence interval 2.36-3.93). No association was observed for body mass index and presence of most comorbidities assessed.

CONCLUSION

The cohort study showed a high incidence of menstrual disorders among women aged ≤54 years, and this observation was supported by the analysis of spontaneous reports. This suggests that a relation between COVID-19 vaccination and menstrual abnormalities is plausible and should be further investigated.

Unexpected vaginal bleeding and COVID-19 vaccination in nonmenstruating women

The association between coronavirus disease 2019 (COVID-19) vaccination and vaginal bleeding among nonmenstruating women is not well studied. The Norwegian Institute of Public Health followed several cohorts throughout the pandemic and early performed a systematic data collection of self-reported unexpected vaginal bleeding in nonmenstruating women. Among 7725 postmenopausal women, 7148 perimenopausal women, and 7052 premenopausal women, 3.3, 14.1, and 13.1% experienced unexpected vaginal bleeding during a period of 8 to 9 months, respectively. In postmenopausal women, the risk of unexpected vaginal bleeding (i.e., postmenopausal bleeding) in the 4 weeks after COVID-19 vaccination was increased two- to threefold, compared to a prevaccination period. The corresponding risk of unexpected vaginal bleeding after vaccination was increased three- to fivefold in both nonmenstruating peri- and premenopausal women. In the premenopausal women, Spikevax was associated with at 32% increased risk as compared to Comirnaty. Our results must be confirmed in future studies.

Prevalence of and risk factors for self-reported menstrual changes following COVID-19 vaccination: a Danish cohort study

STUDY QUESTION

Are there some characteristics that render individuals more susceptible to report menstrual changes following the Coronavirus disease 2019 (COVID-19) vaccination?

SUMMARY ANSWER

We found that 30% of menstruating women reported menstrual changes following COVID-19 vaccination and several potential risk factors including stress, vaccine concerns, severe COVID-19 infection, and immediate vaccine symptoms were associated with these reports.

WHAT IS KNOWN ALREADY

Studies suggest that COVID-19 vaccination might temporarily prolong menstrual cycle length by less than 1 day. Specific characteristics may trigger menstrual changes in temporal relation to the vaccination simply by chance or render women more vigilant to potential menstrual changes after being vaccinated. However, research investigating potential risk factors for reporting menstrual changes following COVID-19 vaccination is limited.

STUDY DESIGN, SIZE, DURATION

A population-based Danish cohort study. Data were collected from May 2021 to December 2021 as a part of the BiCoVac Cohort with the aim of examining non-specific effects following COVID-19 vaccination. The main study population included 13 648 menstruating women aged 16-65 years who completed all surveys, received their first dose of a COVID-19 vaccine during the data collection period, and completed questions related to their menstrual cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Potential risk factors included 14 biological, physical, or psychological measures. Information on most potential risk factors was self-reported and collected before the participants' first COVID-19 vaccination. Information about any menstrual change following COVID-19 vaccination was self-reported at the end of the data collection period. Logistic regression analyses were used to estimate crude and adjusted odds ratios (ORs) with 95% CIs for the association between each potential risk factor and reporting menstrual changes following COVID-19 vaccination.

MAIN RESULTS AND THE ROLE OF CHANCE

Any menstrual change following COVID-19 vaccination was reported by 30% of menstruating women. Most of the potential risk factors were associated with reports of menstrual changes following COVID-19 vaccination. In particular, higher odds were found among women who reported ≥5 immediate vaccine symptoms; OR 1.67 [1.50-1.86], had had a prior severe COVID-19 infection; OR 2.17 [1.40-3.35], had a high-stress level at baseline; OR 1.67 [1.32-2.10], or were concerned about COVID-19 vaccines prior to vaccination; OR 1.92 [1.50-2.45]. Lower odds were found among women with regular menstrual cycles using hormonal contraception; OR 0.71 [0.65-0.78].

LIMITATIONS, REASONS FOR CAUTION

We were unable to address the causal effect of COVID-19 vaccination on the reported menstrual changes, as information about menstrual changes was not available among non-vaccinated women.

WIDER IMPLICATIONS OF THE FINDINGS

The study identified several potential risk factors for reporting menstrual changes following COVID-19 vaccination. Further studies are needed to establish causal associations and the clinical impact of self-reported menstrual changes.

STUDY FUNDING/COMPETING INTEREST(S)

The BiCoVac data collection was funded by TrygFonden (id-number: 153678). No competing interests are declared.

TRIAL REGISTRATION NUMBER

N/A.

Identifying a causal link between prolactin signaling pathways and COVID-19 vaccine-induced menstrual changes

COVID-19 vaccines have been instrumental tools in the fight against SARS-CoV-2 helping to reduce disease severity and mortality. At the same time, just like any other therapeutic, COVID-19 vaccines were associated with adverse events. Women have reported menstrual cycle irregularity after receiving COVID-19 vaccines, and this led to renewed fears concerning COVID-19 vaccines and their effects on fertility. Herein we devised an informatics workflow to explore the causal drivers of menstrual cycle irregularity in response to vaccination with mRNA COVID-19 vaccine BNT162b2. Our methods relied on gene expression analysis in response to vaccination, followed by network biology analysis to derive testable hypotheses regarding the causal links between BNT162b2 and menstrual cycle irregularity. Five high-confidence transcription factors were identified as causal drivers of BNT162b2-induced menstrual irregularity, namely: IRF1, STAT1, RelA (p65 NF-kB subunit), STAT2 and IRF3. Furthermore, some biomarkers of menstrual irregularity, including TNF, IL6R, IL6ST, LIF, BIRC3, FGF2, ARHGDIB, RPS3, RHOU, MIF, were identified as topological genes and predicted as causal drivers of menstrual irregularity. Our network-based mechanism reconstruction results indicated that BNT162b2 exerted biological effects similar to those resulting from prolactin signaling. However, these effects were short-lived and didn't raise concerns about long-term infertility issues. This approach can be applied to interrogate the functional links between drugs/vaccines and other side effects.

Pharmacovigilance signals from active surveillance of mRNA platform vaccines (tozinameran and elasomeran)

INTRODUCTION

Two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines, tozinameran/BNT162b2 (Comirnaty®, Pfizer-BioNTech) and elasomeran/mRNA-1273 (Spikevax®, Moderna), were approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) at the end of 2020, less than a year after the start of the coronavirus disease 2019 (COVID-19) pandemic. In France, the health authorities have requested an intensive vaccination campaign, accompanied by a reinforced and active pharmacovigilance surveillance. This surveillance and analysis of real-life data, based on spontaneous reports received by the French Network of Regional PharmacoVigilance Centers (RFCRPV), has enabled to identify numerous pharmacovigilance signals. Some of them, such as myocarditis and heavy menstrual bleeding, have been confirmed as adverse effects of these vaccines.

METHOD

We propose a descriptive review of the main pharmacovigilance signals identified by the RFCRPV concerning vaccines from the mRNA platform.

RESULTS

Most pharmacovigilance signals were common to both mRNA vaccines: myocarditis, menstrual disorders, acquired haemophilia, Parsonage-Turner syndrome, rhizomelic pseudo-polyarthritis and hearing disorders. Other signals were more specific, such as arterial hypertension with tozinameran or delayed reaction site injection with elasomeran.

CONCLUSION

This non-exhaustive review illustrates the experience of RFCRPV in identifying and monitoring pharmacovigilance signals related to mRNA vaccines in France during the COVID-19 pandemics, and the crucial role of pharmacological and clinical expertise in this area. It also highlights the predominant contribution of spontaneous reporting in the generation of pharmacovigilance signals, particularly for serious and rare adverse events not detected before marketing.

Why we must fight ignorance about COVID-19 vaccines and menstrual cycles

The COVID-19 pandemic has revealed a critical gap in female health science, fueling anxiety, polarized views, and vaccine hesitancy. Although menstrual cycles feel like a niche topic for some, efforts to augment knowledge on the 'fifth vital sign' experienced by more than 300 million people on any given day worldwide are crucial to promote gender equity in health.

Heavy bleeding and other menstrual disturbances in young women after COVID-19 vaccination

BACKGROUND

Many signals of menstrual disturbances as possible side effects of vaccination against COVID-19 have been reported. Our objective was to compare the risk of menstrual disturbances before and after vaccination among women aged 18-30 years in Oslo, Norway.

METHODS

We used electronic questionnaires to collect reports of menstrual disturbances from 3972 women aged 18-30 years, participating in the population-based Norwegian Young Adult Cohort. We examined the occurrence of menstrual disturbances (heavier bleeding than usual, prolonged bleeding, shorter interval between menstruations, longer interval between menstruations, spot bleedings, stronger pain during menstruation, period pain without bleeding) before and after the first and second dose of COVID-19 vaccine. Relative risks (RR) according to vaccination were estimated using a self-controlled case-series design. We performed additional analyses stratified by vaccine brand, contraception/hormone use, and presence of gynecological condition(s).

RESULTS

The prevalence of any menstrual disturbance was 36.7 % in the last menstrual cycle prior the first vaccine dose. The RR for heavier bleeding than usual was 1.90 (95 % CI: 1.69-2.13) after the first vaccine dose and 1.84 (95 % CI 1.66-2.03) after the second dose. Increased risks of prolonged bleeding, shorter interval between menstruations, and stronger pain during menstruation were also observed after both doses. The RRs did not differ with vaccine brand, contraception/hormone use, or presence of gynecological condition(s) for any of the menstrual disturbances.

CONCLUSION

Menstrual disturbances were common regardless of vaccination. We found increased risk of menstrual disturbances after vaccination, particularly for heavier bleeding than usual, prolonged bleeding, shorter interval between menstruations, and stronger period pain. In the future, menstrual characteristics should be included in vaccine trials.

COVID-19 vaccination and menstrual cycle characteristics: A prospective cohort study

We prospectively examined the association between COVID-19 vaccination and menstrual cycle characteristics in an internet-based prospective cohort study. We included a sample of 1,137 participants who enrolled in Pregnancy Study Online (PRESTO), a preconception cohort study of couples trying to conceive, during January 2021-August 2022. Eligible participants were aged 21-45 years, United States or Canadian residents, and trying to conceive without fertility treatment. At baseline and every 8 weeks for up to 12 months, participants completed questionnaires on which they provided information on COVID-19 vaccination and menstrual cycle characteristics, including cycle regularity, cycle length, bleed length, heaviness of bleed, and menstrual pain. We fit generalized estimating equation (GEE) models with a log link function and Poisson distribution to estimate the adjusted risk ratio (RR) for irregular cycles associated with COVID-19 vaccination. We used linear regression with GEE to estimate adjusted mean differences in menstrual cycle length associated with COVID-19 vaccination. We adjusted for sociodemographic, lifestyle, medical and reproductive factors. Participants had 1.1 day longer menstrual cycles after receiving the first dose of COVID-19 vaccine (95 % CI: 0.4, 1.9) and 1.3 day longer cycles after receiving the second dose (95 % CI: 0.2, 2.5). Associations were attenuated at the second cycle post-vaccination. We did not observe strong associations between COVID-19 vaccination and cycle regularity, bleed length, heaviness of bleed, or menstrual pain. In conclusion, COVID-19 vaccination was associated with a ∼1 day temporary increase in menstrual cycle length, but was not appreciably associated with other menstrual cycle characteristics.

Association between SARS-CoV-2 vaccination and healthcare contacts for menstrual disturbance and bleeding in women before and after menopause: nationwide, register based cohort study

OBJECTIVES

To evaluate the risks of any menstrual disturbance and bleeding following SARS-CoV-2 vaccination in women who are premenopausal or postmenopausal.

DESIGN

A nationwide, register based cohort study.

SETTING

All inpatient and specialised outpatient care in Sweden from 27 December 2020 to 28 February 2022. A subset covering primary care for 40% of the Swedish female population was also included.

PARTICIPANTS

2 946 448 Swedish women aged 12-74 years were included. Pregnant women, women living in nursing homes, and women with history of any menstruation or bleeding disorders, breast cancer, cancer of female genital organs, or who underwent a hysterectomy between 1 January 2015 and 26 December 2020 were excluded.

INTERVENTIONS

SARS-CoV-2 vaccination, by vaccine product (BNT162b2, mRNA-1273, or ChAdOx1 nCoV-19 (AZD1222)) and dose (unvaccinated and first, second, and third dose) over two time windows (one to seven days, considered the control period, and 8-90 days).

MAIN OUTCOME MEASURES

Healthcare contact (admission to hospital or visit) for menstrual disturbance or bleeding before or after menopause (diagnosed with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes N91, N92, N93, N95).

RESULTS

2 580 007 (87.6%) of 2 946 448 women received at least one SARS-CoV-2 vaccination and 1 652 472 (64.0%) 2 580 007 of vaccinated women received three doses before the end of follow-up. The highest risks for bleeding in women who were postmenopausal were observed after the third dose, in the one to seven days risk window (hazard ratio 1.28 (95% confidence interval 1.01 to 1.62)) and in the 8-90 days risk window (1.25 (1.04 to 1.50)). The impact of adjustment for covariates was modest. Risk of postmenopausal bleeding suggested a 23-33% increased risk after 8-90 days with BNT162b2 and mRNA-1273 after the third dose, but the association with ChAdOx1 nCoV-19 was less clear. For menstrual disturbance or bleeding in women who were premenopausal, adjustment for covariates almost completely removed the weak associations noted in the crude analyses.

CONCLUSIONS

Weak and inconsistent associations were observed between SARS-CoV-2 vaccination and healthcare contacts for bleeding in women who are postmenopausal, and even less evidence was recorded of an association for menstrual disturbance or bleeding in women who were premenopausal. These findings do not provide substantial support for a causal association between SARS-CoV-2 vaccination and healthcare contacts related to menstrual or bleeding disorders.

Female reproductive health impacts of Long COVID and associated illnesses including ME/CFS, POTS, and connective tissue disorders: a literature review

Long COVID disproportionately affects premenopausal women, but relatively few studies have examined Long COVID's impact on female reproductive health. We conduct a review of the literature documenting the female reproductive health impacts of Long COVID which may include disruptions to the menstrual cycle, gonadal function, ovarian sufficiency, menopause, and fertility, as well as symptom exacerbation around menstruation. Given limited research, we also review the reproductive health impacts of overlapping and associated illnesses including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), connective tissue disorders like Ehlers-Danlos syndrome (EDS), and endometriosis, as these illnesses may help to elucidate reproductive health conditions in Long COVID. These associated illnesses, whose patients are 70%-80% women, have increased rates of dysmenorrhea, amenorrhea, oligomenorrhea, dyspareunia, endometriosis, infertility, vulvodynia, intermenstrual bleeding, ovarian cysts, uterine fibroids and bleeding, pelvic congestion syndrome, gynecological surgeries, and adverse pregnancy complications such as preeclampsia, maternal mortality, and premature birth. Additionally, in Long COVID and associated illnesses, symptoms can be impacted by the menstrual cycle, pregnancy, and menopause. We propose priorities for future research and reproductive healthcare in Long COVID based on a review of the literature. These include screening Long COVID patients for comorbid and associated conditions; studying the impacts of the menstrual cycle, pregnancy, and menopause on symptoms and illness progression; uncovering the role of sex differences and sex hormones in Long COVID and associated illnesses; and addressing historical research and healthcare inequities that have contributed to detrimental knowledge gaps for this patient population.

Adverse effects, perceptions and attitudes related to BNT162b2, mRNA-1273 or JNJ-78436735 SARS-CoV-2 vaccines: Population-based cohort

Long-term control of SARS-CoV-2 requires effective vaccination strategies. This has been challenged by public mistrust and the spread of misinformation regarding vaccine safety. Better understanding and communication of the longer-term and comparative experiences of individuals in the general population following vaccination are required. In this population-based longitudinal study, we included 575 adults, randomly selected from all individuals presenting to a Swiss reference vaccination center, for receipt of BNT162b2, mRNA1273, or JNJ-78436735. We assessed the prevalence, onset, duration, and severity of self-reported adverse effects over 12 weeks following vaccination. We additionally evaluated participants' perceptions of vaccines, trust in public health authorities and pharmaceutical companies, and compliance with public health measures. Most participants reported at least one adverse effect within 12 weeks following vaccination. Adverse effects were mostly mild or moderate, resolved within three days, and rarely resulted in anaphylaxis or hospitalizations. Female sex, younger age, higher education, and receipt of mRNA-1273 were associated with reporting adverse effects. Compared to JNJ-78436735 recipients, a higher proportion of mRNA vaccine recipients agreed that vaccination is important, and trusted public health authorities. Our findings provide real-world estimates of the prevalence of adverse effects following SARS-CoV-2 vaccination and highlight the importance of transparent communication to ensure the success of current or future vaccination campaigns.

COVID-19 vaccination and menstrual disorders among women: Findings from a meta-analysis study

BACKGROUND

COVID - 19 vaccine can lead to various local and systemic side effects, including menstrual irregularities in women. There is no robust quantitative evidence of the association between the COVID - 19 vaccine and menstrual irregularities. A meta-analysis was performed to estimate the pooled prevalence of a range of menstrual disorders that may occur in women following COVID - 19 vaccination.

METHODS

After searching for epidemiological studies, we systematically performed a meta-analysis on PubMed/Medline, EMBASE, and Science Direct. Sixteen studies were finally included in the study. We estimated the pooled prevalence and corresponding 95 % confidence intervals (CIs) for a group of menstrual disorders, including menorrhagia, polymenorrhea, abnormal cycle length, and oligomenorrhea. Heterogeneity was assessed using the I² statistic and the Q test.

RESULTS

Overall, the pooled prevalence of menorrhagia was 24.24 % (pooled prevalence 24.24 %; 95 % CI: 12.8-35.6 %). The pooled prevalence of polymenorrhea was 16.2 % (pooled prevalence: 16.2 %; 95 % CI: 10.7-21.6 %). The pooled prevalence of abnormal cycle length was relatively lower than that of the other disorders (pooled prevalence: 6.6 %; 95 % CI: 5.0-8.2 %). The pooled prevalence of oligomenorrhea was 22.7 % (95 % CI: 13.5-32.0 %).

CONCLUSION

The findings indicate that menorrhagia, oligomenorrhea, and polymenorrhea were the most common menstrual irregularities after vaccination. The findings also suggest that a relatively high proportion of women suffer from menstrual irregularities. Further longitudinal studies are needed to confirm the causal relationship between COVID-19 vaccination and menstrual irregularities.

SARS-CoV-2, fertility and assisted reproduction

BACKGROUND

In 2020, SARS-CoV-2 and the COVID-19 pandemic had a huge impact on the access to and provision of ART treatments. Gradually, knowledge of the virus and its transmission has become available, allowing ART activities to resume. Still, questions on the impact of the virus on human gametes and fertility remain.

OBJECTIVE AND RATIONALE

This article summarizes published data, aiming to clarify the impact of SARS-CoV-2 and the COVID-19 disease on human fertility and assisted reproduction, as well as the impact of vaccination, and from this, provide answers to questions that are relevant for people contemplating pregnancy and for health care professionals.

SEARCH METHODS

PUBMED/MEDLINE and the WHO COVID-19 database were searched from inception to 5 October 2022 with search terms focusing on 'SARS-CoV-2' and gametes, embryos, reproductive function, fertility and ART. Non-English studies and papers published prior to 2020 were excluded, as well as reviews and non-peer reviewed publications. Full papers were assessed for relevance and quality, where feasible.

OUTCOMES

From the 148 papers included, the following observations were made. The SARS-CoV-2-binding proteins, angiotensin-converting enzyme 2 (ACE2) and type II transmembrane serine protease (TMPRSS2), are expressed in the testis, but co-expression remains to be proven. There is some evidence of SARS-CoV-2 RNA in the ejaculate of COVID-19 patients with severe disease, but not in those with mild/moderate disease. SARS-CoV-2 infection can impair spermatogenesis, but this seems to resolve after one spermatogenic cycle. Testosterone levels seem to be lower during and after COVID-19, but long-term data are lacking; disease severity may be associated with testosterone levels. COVID-19 cannot be considered a sexually transmitted disease. There is no co-expression of ACE2 and TMPRSS2 in the myometrium, uterus, ovaries or fallopian tubes. Oocytes seem to have the receptors and protease machinery to be susceptible to SARS-CoV-2 infection; however, viral RNA in oocytes has not been detected so far. Women contemplating pregnancy following COVID-19 may benefit from screening for thyroid dysfunction. There is a possible (transient) impact of COVID-19 on menstrual patterns. Embryos, and particularly late blastocysts, seem to have the machinery to be susceptible to SARS-CoV-2 infection. Most studies have not reported a significant impact of COVID-19 on ovarian reserve, ovarian function or follicular fluid parameters. Previous asymptomatic or mild SARS-CoV-2 infection in females does not seem to negatively affect laboratory and clinical outcomes of ART. There are no data on the minimum required interval, if any, between COVID-19 recovery and ART. There is no evidence of a negative effect of SARS-CoV-2 vaccination on semen parameters or spermatogenesis, ovarian function, ovarian reserve or folliculogenesis. A transient effect on the menstrual cycle has been documented. Despite concerns, cross reactivity between anti-SARS-CoV-2 spike protein antibodies and Syncytin-1, an essential protein in human implantation, is absent. There is no influence of mRNA SARS-CoV-2 vaccine on patients' performance during their immediate subsequent ART cycle. Pregnancy rates post-vaccination are similar to those in unvaccinated patients.

WIDER IMPLICATIONS

This review highlights existing knowledge on the impact of SARS-CoV-2 infection or COVID-19 on fertility and assisted reproduction, but also identifies gaps and offers suggestions for future research. The knowledge presented should help to provide evidence-based advice for practitioners and couples contemplating pregnancy alike, facilitating informed decision-making in an environment of significant emotional turmoil.

The effect of COVID-19 vaccinations on menstrual cycle and serum anti-Mullerian hormone levels in reproductive age women

The aim of this prospective cohort study was to investigate the effect of coronavirus disease 2019 (COVID-19) vaccinations on menstrual cycle and ovarian reserve in reproductive aged-women. Health care providers (n = 258) vaccinated with inactivated (CoronaVac) and mRNA based (Pfizer-BioNTech®) COVID-19 vaccines were included. All subjects completed a gynaecological and menstrual history questionnaire and Anti-Mullerian Hormone (AMH) levels were measured in serum samples collected before first vaccination and at 1st, 3rd, 6th and 9th months. The prevalence of new-onset menstrual dysregulation following vaccination was 20.6% and it was statistically significant compared to baseline (p = 0.001). Menstrual pattern turned back to normal in 59.6% of vaccinated women. Serum AMH levels gradually decreased until 6th month of follow-up compared to baseline (p < 0.001). A significant increase in serum AMH level was observed at 9th month of follow-up compared to 6th month follow-up levels (p < 0.001). The decrease in serum AMH level was statistically significant regardless of serum anti SARS-CoV-2 antibody levels, subgroups of age, occupation, menstrual dysregulation following vaccination and presence of gynaecological diseases. In conclusion, vaccination against SARS-CoV-2 causes a transient decrease on serum AMH levels and moderate irregularities in menstrual pattern increasing with age and is mostly reversible.

[Long COVID-A New Challenge in Medicine: Focus on Pregnancy and Breastfeeding]

Long COVID (coronavirus disease) has been described as a new multi-organ disease, which appears to be more prevalent in women than in men. Pregnant and breastfeeding women are a special subgroup of patients to consider with long COVID, as only scarce data have been collected to date. Menstrual changes are commonly observed during or after COVID-19; some studies also attribute slight changes of cycle length to previous inoculation against the virus. Pregnant women who have a symptomatic infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) are at a higher risk for adverse outcomes and pregnancy-associated complications. Moreover, more and robust data are required to evaluate vertical transmission. COVID vaccines are the most effective tool against the pandemic, as they prevent infection, but also appear to be able to ease long COVID symptoms. Vaccines have been proven safe and effective in both pregnant and breastfeeding women. This article aims to present current data on long COVID in pregnant and breastfeeding women and elucidate risk factors and possible treatment options.

[Association of SARS-CoV-2 infection and administration of COVID-19 vaccines with alterations in the menstrual cycle. Literature review]

A number of factors can affect a woman's menstrual cycle, including diseases or drugs, such as COVID-19 disease and vaccinations. The aim of this review is to explore the studies published to date that have studied the presence of alterations that may be related to COVID-19 or vaccination against the SARS-CoV-2 virus.We conducted a review in the PubMed database, selecting 10 articles in which the menstrual cycle of adult women of childbearing age was studied, 3 of them in which the participants had been diagnosed with COVID-19 and 7 in which the participants had been vaccinated against the SARS-CoV-2 virus.Regarding COVID-19-related disturbances, 16%-47.2% of the participants presented a prolongation of their cycle, which was more frequent in those who reported more COVID-19 symptoms, and which normalised after 1-2 cycles.Regarding the alterations described after SARS-CoV-2 vaccination, 45%-78% of participants reported menstrual cycle alterations, with disparate results for the different parameters analysed, except that the alterations resolved in about 2 months.Both COVID-19 disease and vaccination appear to be associated with the occurrence of menstrual disturbances, which are limited in time and not severe. However, studies are scarce to date, and it is important to continue to develop studies that provide scientific evidence.

Menstrual cycle changes: A cross-sectional study of Saudi females following SARS-CoV-2 infection

Temporary changes in the menstrual cycle have recently been reported following SARS-CoV-2 vaccination. In the current study, we aimed to screen menstrual cycle changes following SARS-CoV-2 infection in Saudi Arabia. The type and duration of these changes have been screened in relation to the severity of coronavirus disease symptoms and vaccination status. In total, 956 individuals responded: sixty-nine did not get the COVID-19 vaccine, while the remaining were vaccinated with either a single dose of ChAdOx1 vaccine (n:45) or BNT162b2 vaccine (n: 142) or two doses of the vaccine (n:700) using BNT162b2 (n:477), ChAdOx1 (n:89) or ChAdOx1/ BNT162b2 (n:134). Approximately 26.1% (18/69) of the subjects who did not receive the SARS-CoV-2 vaccine and 15.3% (29/188) and 26.4% (185/700) of the subjects who received single and double doses of the vaccines, respectively, reported menstrual cycle changes. The persistence of menstrual cycle changes for more than six months was reported by 6.4% (61/956) of the participants. These changes were significantly correlated with the severity of COVID-19 infection. We concluded that menstrual cycle changes, associated with COVID-19 infection, increase due to the severity of COVID-19 infection. Thus, menstrual cycle changes are among the long-term effects associated with COVID-19 infection.

The type of SARS-CoV-2 vaccine does not affect ovarian function in assisted reproduction cycle

OBJECTIVE

To assess whether vaccination or the type of vaccine against SARS-CoV-2 affects ovarian function in an assisted reproduction treatment.

DESIGN

A retrospective and observational study.

SETTING

University-affiliated private in vitro fertilization (IVF) center.

PATIENT(S)

Five hundred one patients who had received the complete vaccination schedule.

INTERVENTION(S)

Treatment before and after vaccination.

MAIN OUTCOME MEASURE(S)

Parameters for both reproductive outcomes and IVF results in patients vaccinated RESULT(S): We included 510 patients, distributed as follows: 13.5% (n = 69) received a viral vector vaccine, either the adenovirus serotype 26 vector vaccine (Ad26.CoV2.S; Janssen; n = 31) or the chimpanzee adenovirus vector vaccine (ChAdOx; AstraZeneca; n = 38). The remaining 86.5% (n = 441) received an messenger RNA vaccine from either Pfizer-BioNTech (n = 336) or Moderna (n = 105). Sample size for the unexposed women was n = 1190. No differences were found in any of the evaluated parameters for both reproductive outcomes and IVF results in patients vaccinated with any adenovirus or messenger RNA vaccine. When we compared the results after vaccination with different types of vaccines between the exposed and unexposed groups, and similar results were obtained in the days of stimulation or the doses of administered follicle stimulating hormone. Finally, the numbers of oocytes were as follows: Johnson & Johnson (9.2 ± 2.6), AstraZeneca (7.7 ± 1.2), Moderna (11.3 ± 1.8), Pfizer (12.6 ± 1.0), and the unvaccinated group (10.2 ± 1.5), P=0.057.

CONCLUSION(S)

These early results suggest no measurable detrimental effect on reproductive outcomes, regardless of the type of vaccine received.

COVID-19 vaccination and menstruation

COVID-19 vaccination causes small changes to menstruation that quickly resolve

Covid-19 vaccination and menstrual cycle length in the Apple Women's Health Study

COVID-19 vaccination may be associated with change in menstrual cycle length following vaccination. We estimated covariate-adjusted differences in mean cycle length (MCL), measured in days, between pre-vaccination cycles, vaccination cycles, and post-vaccination cycles within vaccinated participants who met eligibility criteria in the Apple Women's Health Study, a longitudinal mobile-application-based cohort of people in the U.S. with manually logged menstrual cycles. A total of 9652 participants (8486 vaccinated; 1166 unvaccinated) contributed 128,094 cycles (median = 10 cycles per participant; inter-quartile range: 4-22). Fifty-five percent of vaccinated participants received Pfizer-BioNTech's mRNA vaccine, 37% received Moderna's mRNA vaccine, and 8% received the Johnson & Johnson/Janssen (J&J) vaccine. COVID-19 vaccination was associated with a small increase in MCL for cycles in which participants received the first dose (0.50 days, 95% CI: 0.22, 0.78) and cycles in which participants received the second dose (0.39 days, 95% CI: 0.11, 0.67) of mRNA vaccines compared with pre-vaccination cycles. Cycles in which the single dose of J&J was administered were, on average, 1.26 days longer (95% CI: 0.45, 2.07) than pre-vaccination cycles. Post-vaccination cycles returned to average pre-vaccination length. Estimated follicular phase vaccination was associated with increased MCL in cycles in which participants received the first dose (0.97 days, 95% CI: 0.53, 1.42) or the second dose (1.43 days, 95% CI: 1.06, 1.80) of mRNA vaccines or the J&J dose (2.27 days, 95% CI: 1.04, 3.50), compared with pre-vaccination cycles. Menstrual cycle change following COVID-19 vaccination appears small and temporary and should not discourage individuals from becoming vaccinated.

Effect of the COVID-19 Vaccine on the Menstrual Cycle among Females in Saudi Arabia

Background

The number of reports of menstrual changes after COVID-19 vaccination in the Saudi population is still unknown. Therefore, this study aimed to assess the effect of the COVID-19 vaccine(Pfizer, AstraZeneca, and Moderna) on the menstrual cycle among females in Saudi Arabia.

Methods

This descriptive cross-sectional study was conducted in Saudi Arabia at Umm Al-Qura University (UQU) from August 2021 to February 2022. Data was collected through a previously validated online questionnaire.

Results

A total of 2338 participants who received the first dose of the COVID-19 vaccine participated in this study; 1606 (68.7%) of them received the second dose in addition to the first. The mean age of the study participants was 35.4±9.5 years. No significant associations were found between the type of COVID-19 vaccine and the impact on the menstrual cycle, either for the first or second dose (P-values > 0.05). A significant association was found only between the first dose vaccination day and the impact on the menstrual cycle in the second question of "After receiving the COVID-19 vaccine, your next period was" (P-value ≤ 0.05). Significant associations were found between the second dose vaccination day and the impact on the menstrual cycle in the first and second questions of "After receiving the COVID-19 vaccine, your next period was", and "After receiving the first dose, your next period was," respectively (P-values ≤ 0.05).

Conclusion

The study found a potential association between the COVID-19 vaccine and menstrual cycle irregularities, which could impact females' quality of life.

A prospective study of the association between SARS-CoV-2 infection and COVID-19 vaccination with changes in usual menstrual cycle characteristics

BACKGROUND

Despite anecdotal reports, the impacts of SARS-CoV-2 infection or COVID-19 vaccination on menstrual health have not been systemically investigated.

OBJECTIVE

This study aimed to examine the associations of SARS-CoV-2 infection and COVID-19 vaccination with menstrual cycle characteristics.

STUDY DESIGN

This study prospectively observed 3858 premenopausal women in the Nurses' Health Study 3 living in the United States or Canada who received biannual follow-up questionnaires between January 2011 and December 2021 and completed additional monthly and quarterly surveys related to the COVID-19 pandemic between April 2020 and November 2021. History of positive SARS-CoV-2 test, COVID-19 vaccination status, and vaccine type were self-reported in surveys conducted in 2020 and 2021. Current menstrual cycle length and regularity "before COVID-19" were reported at baseline between 2011 and 2016, and current menstrual cycle length and regularity "after COVID-19" were reported in late 2021. Pre- to post-COVID change in menstrual cycle length and regularity was calculated between reports. Logistic or multinomial logistic regression models were used to assess the associations between SARS-CoV-2 infection and COVID-19 vaccination and change in menstrual cycle characteristics.

RESULTS

The median age at baseline and the median age at end of follow-up were 33 years (range, 21-51) and 42 years (range, 27-56), respectively, with a median follow-up time of 9.2 years. This study documented 421 SARS-CoV-2 infections (10.9%) and 3527 vaccinations (91.4%) during follow-up. Vaccinated women had a higher risk of increased cycle length than unvaccinated women (odds ratio, 1.48; 95% confidence interval, 1.00-2.19), after adjusting for sociodemographic and behavioral factors. These associations were similar after in addition accounting for pandemic-related stress. COVID-19 vaccination was only associated with change to longer cycles in the first 6 months after vaccination (0-6 months: odds ratio, 1.67 [95% confidence interval, 1.05-2.64]; 7-9 months: odds ratio, 1.43 [95% confidence interval, 0.96-2.14]; >9 months: odds ratio, 1.41 [95% confidence interval, 0.91-2.18]) and among women whose cycles were short, long, or irregular before vaccination (odds ratio, 2.82 [95% confidence interval, 1.51-5.27]; odds ratio, 1.10 [95% confidence interval, 0.68-1.77] for women with normal length, regular cycles before vaccination). Messenger RNA and adenovirus-vectored vaccines were both associated with this change. SARS-CoV-2 infection was not associated with changes in usual menstrual cycle characteristics.

CONCLUSION

COVID-19 vaccination may be associated with short-term changes in usual menstrual cycle length, particularly among women whose cycles were short, long, or irregular before vaccination. The results underscored the importance of monitoring menstrual health in vaccine clinical trials. Future work should examine the potential biological mechanisms.

SARS-CoV-2-The Role of Natural Immunity: A Narrative Review

BACKGROUND

Both natural immunity and vaccine-induced immunity to COVID-19 may be useful to reduce the mortality/morbidity of this disease, but still a lot of controversy exists.

AIMS

This narrative review analyzes the literature regarding these two immunitary processes and more specifically: (a) the duration of natural immunity; (b) cellular immunity; (c) cross-reactivity; (d) the duration of post-vaccination immune protection; (e) the probability of reinfection and its clinical manifestations in the recovered patients; (f) the comparisons between vaccinated and unvaccinated as to the possible reinfections; (g) the role of hybrid immunity; (h) the effectiveness of natural and vaccine-induced immunity against Omicron variant; (i) the comparative incidence of adverse effects after vaccination in recovered individuals vs. COVID-19-naïve subjects.

MATERIAL AND METHODS

through multiple search engines we investigated COVID-19 literature related to the aims of the review, published since April 2020 through July 2022, including also the previous articles pertinent to the investigated topics.

RESULTS

nearly 900 studies were collected, and 246 pertinent articles were included. It was highlighted that the vast majority of the individuals after suffering from COVID-19 develop a natural immunity both of cell-mediated and humoral type, which is effective over time and provides protection against both reinfection and serious illness. Vaccine-induced immunity was shown to decay faster than natural immunity. In general, the severity of the symptoms of reinfection is significantly lower than in the primary infection, with a lower degree of hospitalizations (0.06%) and an extremely low mortality.

CONCLUSIONS

this extensive narrative review regarding a vast number of articles highlighted the valuable protection induced by the natural immunity after COVID-19, which seems comparable or superior to the one induced by anti-SARS-CoV-2 vaccination. Consequently, vaccination of the unvaccinated COVID-19-recovered subjects may not be indicated. Further research is needed in order to: (a) measure the durability of immunity over time; (b) evaluate both the impacts of Omicron BA.5 on vaccinated and healed subjects and the role of hybrid immunity.