Gender differences in vaccine therapy: where are we in COVID-19 pandemic?

When estrogen deficiency meets immune responses induced by rabies vaccination

Estrogen deficiency in postmenopausal women is accompanied by immune status alterations, leading to a chronic low-grade inflammatory phenotype. Immediate rabies postexposure prophylaxis (PEP) following a transdermal bite or scratch from a rabies-infected animal is urgently needed. However, whether immune alterations in postmenopausal women influence the reaction to rabies vaccination remains unclear. Bilateral ovariectomized (OVX) and Sham mice were immunized with modified live vaccine RABV LBNSE. LBNSE immunization had no obvious pathological effect on the mice in either group and effectively protected all mice from RABV attack. Although 100% protection was found, the reduction rate of viral neutralizing antibody titers in the LBNSE-OVX mice was greater than that in the LBNSE-Sham mice. LBNSE immunization recruited/activated fewer dendritic cells (DCs) and B cells in the lymph nodes, while more B cells were detected in the blood of LBNSE-OVX mice than in that of LBNSE-Sham mice. Th1 and Th2 immune responses are both rapidly induced in LBNSE-OVX-subjected mice and are inclined toward a Th2-biased immune response. LBNSE immunization in OVX mice elicited similar amounts of RABV-specific CD4+ and CD8+ T cells as those in Sham mice. Our data revealed that the protective efficacy of rabies vaccination was slightly decreased by estrogen deficiency and that DC and B lymphocyte recruitment/activation and Th-mediated responses in splenocytes were partly altered; however, rabies vaccination offered sufficient protection against RABV within the observation period, helping alleviate anxiety related to rabies virus exposure after menopause. Additional measures might be helpful to improve long-term effective protection in postmenopausal women.IMPORTANCEMenopause has a distinct effect on the decrease in the female immune system, and whether protection efficacy after rabies vaccination in postmenopausal women is influenced requires evaluation. Our findings demonstrated that although viral neutralizing antibody (VNA) titers in the LBNSE-OVX mice were similar to those in the LBNSE-Sham mice, VNAs declined faster than those in the LBNSE-Sham mice within the observation period. Fewer dendritic cells in the lymph nodes were recruited/activated in LBNSE-OVX mice than in LBNSE-Sham mice, whereas B cells in the lymph nodes and peripheral blood exhibited the opposite tendency. Th2-biased immune responses were induced in LBNSE-OVX mice, and no significant changes were observed in RABV-specific CD4+ or CD8+ T cells. These results provide evidence that rabies vaccination could provide effective protection for postmenopausal women within the observation period, but other measures might be needed to improve protection, which is beneficial for alleviating anxiety of menopausal women when facing rabies immunization.

COVID-19 booster doses reduce sex disparities in antibody responses among nursing home residents

BACKGROUND

Data suggest that antibody responses following COVID-19 vaccines are a correlate of protection. Some studies, including the clinical trials of COVID-19 mRNA vaccines, did not stratify and evaluate whether antibody responses to COVID-19 vaccines differed between the sexes or with aging. This gap in research is particularly relevant for older populations such as nursing home residents (NHR). We hypothesized that sex differences in vaccine-induced antibody responses may intersect with age and be diminished among older adults residing in nursing homes.

METHODS

We analyzed serum samples from 638 NHRs collected serially after the primary two-dose series and three subsequent booster doses of mRNA SARS-CoV-2 vaccinations. We analyzed anti-Spike IgG and neutralizing antibody titers to the Wuhan and Omicron BA.4/5 variant strains. Mixed-effects models predicting log-transformed titers were estimated to compare responses across vaccine doses, focusing on sex-differential responses. For detected post-dose sex differences, additional sample times were analyzed to assess the duration of the difference.

RESULTS

Following the primary series, female NHRs with a prior history of SARS-CoV-2 infection had significantly higher Wuhan anti-Spike antibodies and neutralizing antibody titers than male NHRs with differences persisting up to nine months post-vaccination. Subsequent monovalent booster doses and a bivalent booster dose eliminated this disparity. We did not detect any differential response to the Omicron BA.4/5 variant.

CONCLUSIONS

The blunting of sex differences in antibody response observed following the primary series by the 1st booster dose underscores the importance of booster vaccination in this population.

Sex differences in response to HBV vaccination in a cohort of health care workers

Globally, healthcare workers (HCWs) are at greater risk of contracting Hepatitis B virus (HBV) infection than the general population, due to their frequent contact with blood or body fluids. For this reason, WHO underlined the importance of HBV immunization for all HCWs. Although sex is now considered one of the key factors influencing the intensity and duration of the immune response to vaccines, sex-specific analysis of vaccine-induced anti-HBs antibodies is rarely conducted. Our study aimed to evaluate the anti-HBs antibodies' long-lasting protective titers in male and female HCWs to identify sex differences in the humoral response to the HBV vaccine. The study was conducted on 2106 HCWs (1636 females and 470 males) working at the Padova University Hospital, Italy. Our results report significantly higher anti-HBs levels in female HCWs than in males, particularly when considering HCWs for whom the elapsed time since vaccination is greater than 10 years, suggesting a greater persistence of anti-HBs in females. In conclusion, our findings could contribute to understanding differences in the antibody response to the HBV vaccine between male and female subjects and improving vaccination strategies for HCWs.

Role of Xenosialylation in Post-Infectious and Post-Vaccination Complications, Including Covid-19 and Anti-SARS-CoV-2 Vaccination

The host glycosylation mechanism, with sialic acids as a key component, is essential for synthesizing carbohydrate components in viral glycoproteins. We hypothesize a correlation between the presence of the Neu5Gc on the host tissue and the development of infectious complications, adverse vaccine reactions, and autoimmune diseases. In certain mammals, including humans, the loss of the Cytidine Monophospho-N-Acetylneuraminic Acid Hydroxylase gene (negative-CMAH) prevents the synthesis of Neu5Gc, which acts as a Mammalian-associated Carbohydrate Antigen (MCA), (XeSiAs-Neu5Gc). When negative-CMAH species consume products from positive-CMAH mammals or are exposed to non-human cell-derived medicines, Neu5Gc can be integrated into their glycocalyx through a process called xenosialylation, eliciting an inflammatory response (xenosialitis) and prompting the production of circulating anti-Neu5Gc antibodies aimed at eliminating Neu5Gc. We hypothesize that in the case of xenosialylation, neutralizing antiviral antibodies from infections or vaccinations-including those for SARS-CoV-2-may cross-react with the XeSiAs-Neu5Gc glycans, as these resemble viral envelope antigens produced by the host's glycosylation. Additionally, circulating anti-Neu5Gc antibodies may also react with other circulating antibodies, including newly formed antiviral ones with a XeSiAs-Neu5Gc-contaminated Fc region. This can lead to the serum removal of the anti-inflammatory antibodies, leaving only hyperinflammatory IgG agalactosylated antibodies. Such conditions are also seen in various inflammatory and autoimmune diseases. We hypothesize that the combination of antibody cross-reaction and the removal of the XeSiAs-Neu5Gc-contaminated Fc region anti-inflammatory antibodies may intensify severe inflammatory responses like cytokine storms and coagulopathies in COVID-19 patients and those vaccinated. Assessing serum levels of total XeSiAs-Neu5Gc antibodies could be a valuable method for identifying patients at risk of severe complications from viral infections and vaccinations, including SARS-CoV-2. This strategy may also deepen our understanding of the pathogenesis of autoimmune diseases linked to post-infectious and post-vaccination complications, particularly for viruses utilizing the host glycosylation machinery, such as SARS-CoV-2, IAV, EBV, and others.

COVID-19 vaccination and postmenopausal bleeding: a retrospective cohort study

OBJECTIVE

COVID-19 vaccination has been related to menstrual irregularities; however, the effect on postmenopausal women is unknown. The aim of this study was to analyze the prevalence of postmenopausal bleeding (PMB) after COVID-19 vaccination.

METHODS

A retrospective study was conducted in the Department of Gynecology in Hospital del Mar. Consecutive postmenopausal women with data available and endometrial biopsy were included between February 2021 and January 2022. Patients were stratified between COVID-19 vaccinated and unvaccinated groups. PMB after 30 days from last vaccine dose was considered unrelated to vaccine. Endometrial pathology diagnoses were stratified into benign or malignant. Univariable and multivariable of regression analysis on variables potentially associated with PMB was performed.

RESULTS

A total of 381 patients were included, 91 in the vaccinated group and 290 in the unvaccinated group. Prevalence of PMB in the vaccinated group was 75.8% compared to 59.0% in the unvaccinated group (p < 0.005). No increase in endometrial malignant pathology was observed among the vaccinated group (p = 0.189). Multivariable analysis that correlates factors associated with PMB suggests COVID-19 vaccine and malignant endometrial biopsy as independent risk variables.

CONCLUSIONS

A higher prevalence of PMB was associated with COVID-19 vaccine. Endometrial histological results showed no association with COVID-19 vaccination, but endometrial biopsy should be performed for PMB.

Association between sex hormones and anti-S/RBD antibody responses to COVID-19 vaccines in healthcare workers

Healthcare workers (HCWs) are the target population for vaccination against coronavirus disease (COVID-19) as they are at a high risk of exposure and transmission of pathogens to patients. Neutralizing antibodies developed after COVID-19 vaccination decline within few months of vaccination. Several factors, including age and sex, can affect the intensity, efficacy, and duration of immune response to vaccines. However, sex-specific analyses of humoral responses to COVID-19 vaccines are lacking. This study aimed to evaluate sex-based differences in anti-S/RBD (Receptor Binding Domain) responses at three different time points after the second dose of mRNA COVID-19 vaccine in HCWs in relation to age, and to investigate the role of sex hormones as potential markers of response. Anti-S/RBD levels after two doses of the mRNA vaccine were collected from 521 HCWs naïve to COVID-19, working at two Italian Clinical Centers. Multiple regression analysis was applied to evaluate the association between anti-S levels and sex, age, and plasma levels of sex hormones. Significantly higher anti-S/RBD response to the COVID-19 vaccination was found in female HCWs, and a significant and more abrupt decline in response with time was observed in women than that in men. A novel, positive association of testosterone plasma levels and higher anti-S levels in male HCWs was found, suggesting its potential role as sex specific marker in males. In conclusion, understanding the sex-based differences in humoral immune responses to vaccines may potentially improve vaccination strategies and optimize surveillance programs for HCWs.

The Safety and Effectiveness of mRNA Vaccines Against SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in numerous deaths worldwide, along with devastating economic disruptions, and has posed unprecedented challenges to healthcare systems around the world. In the wake of COVID-19's emergence in 2019, a variety of vaccine technologies were formulated and developed, including those that drew from the technology employed in messenger RNA (mRNA) vaccines, designed to curb the disease's transmission and manage the pandemic. mRNA vaccine has several advantages over traditional ones, and hence its development has received considerable attention recently. Researchers believe the mRNA vaccine technology will emerge as the leading technology because it is potent, inexpensive, rapidly developed, and safe. This article provides an overview of mRNA vaccines with a special focus on the efficacy and safety of the Moderna and Pfizer-BioNTech mRNA vaccines against the different variants of COVID-19 and compare them with the Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines. The clinical data reviewed in this article demonstrate that the currently authorized Moderna and Pfizer-BioNTech mRNA vaccines are highly safe and potent against different variants of COVID-19, especially in comparison with Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines.

Self-reported symptoms after COVID-19 vaccination. Distinct sex, age, and geographical outcomes in Lebanese and Italian cohorts

Following the COVID-19 discovery in December 2019, different vaccines were authorized in 2021 in Italy and Lebanon, but side effects and the impact of sex and age remained partly explored. We designed a web-based "Google Form" questionnaire to record self-reported systemic and local side effects up to 7 days after 1st and 2nd dose of the vaccine in two distinct Italian and Lebanese cohorts. Twenty-one questions in Italian and Arabic languages explored the prevalence and severity of 13 symptoms. Results were compared with respect to living country, timing, sex, and age classes. A total of 1,975 Italian subjects (age 42.9 ± SD16.8 years; 64.5% females) and 822 Lebanese subjects (age 32.5 ± SD15.9 years; 48.8% females) joined the study. The most common symptoms in both groups were injection site pain, weakness, and headache after the 1st and 2nd doses. The rate of post-vaccinal symptoms and the severity score were significantly higher in females than in males and progressively decreased with increasing age following both doses. We find that among two populations from the Mediterranean basin, the anti-COVID-19 vaccine generates mild age and sex-dependent adverse effects, with ethnic differences and prevalent symptoms rate and severity in females.

A comparative analysis on serious adverse events reported for COVID-19 vaccines in adolescents and young adults

This study aims to assess the safety profile of COVID-19 vaccines (mRNA and viral vector vaccines) in teenagers and young adults, as compared to Influenza and HPV vaccines, and to early data from Monkeypox vaccination in United States.

Methods

We downloaded data from the Vaccine Adverse Event Reporting System (VAERS) and collected the following Serious Adverse Events (SAEs) reported for COVID-19, Influenza, HPV and Monkeypox vaccines: deaths, life-threatening illnesses, disabilities, hospitalizations. We restricted our analysis to the age groups 12-17 and 18-49, and to the periods December 2020 to July 2022 for COVID-19 vaccines, 2010-2019 for Influenza vaccines, 2006-2019 for HPV vaccines, June 1, 2022 to November 15, 2022 for Monkeypox vaccine. Rates were calculated in each age and sex group, based on an estimation of the number of administered doses.

Results

Among adolescents the total number of reported SAEs per million doses for, respectively, COVID-19, Influenza and HPV vaccines were 60.73, 2.96, 14.62. Among young adults the reported SAEs rates for, respectively, COVID-19, Influenza, Monkeypox vaccines were 101.91, 5.35, 11.14. Overall, the rates of reported SAEs were significantly higher for COVID-19, resulting in a rate 19.60-fold higher than Influenza vaccines (95% C.I. 18.80-20.44), 4.15-fold higher than HPV vaccines (95% C.I. 3.91-4.41) and 7.89-fold higher than Monkeypox vaccine (95% C.I. 3.95-15.78). Similar trends were observed in teenagers and young adults with higher Relative Risks for male adolescents.

Conclusion

The study identified a risk of SAEs following COVID-19 vaccination which was markedly higher compared to Influenza vaccination and substantially higher compared to HPV vaccination, both for teenagers and young adults, with an increased risk for the male adolescents group. Initial, early data for Monkeypox vaccination point to significantly lower rates of reported SAEs compared to those for COVID-19 vaccines. In conclusion these results stress the need of further studies to explore the bases for the above differences and the importance of accurate harm-benefit analyses, especially for adolescent males, to inform the COVID-19 vaccination campaign.

The Immunogenicity and Safety of Three Types of SARS-CoV-2 Vaccines in Adult Patients with Immune-Mediated Inflammatory Diseases: A Longitudinal Cohort Study

Patients with immune-mediated inflammatory diseases (IMID) were seldom enrolled in the studies of SARS-CoV-2 vaccines, and real-world data regarding the immunogenicity of different types of vaccines is limited. We aimed to assess the immunogenicity and safety of three types of vaccines (AZD1222, mRNA-1273, and BNT162b2) in 253 patients with IMID and 30 healthcare workers (HCWs). Plasma levels of IgG-antibody against SARS-CoV-2 targeting the receptor-binding domain of spike protein (anti-S/RBD-IgG) were determined by chemiluminescent immunoassay 3–4 weeks after the first-dose and second-dose vaccination. The positive rate and titers of anti-S/RBD-IgG were significantly higher in mRNA-1273 or BNT162b2 than in the AZD1222 vaccine. Immunogenicity was augmented after the second dose of any vaccine type in all IMID patients, suggesting that these patients should complete the vaccination series. Anti-S/RBD-IgG titers after first-dose vaccination were significantly lower in RA patients than pSS patients, but there was no significant difference after second-dose vaccination among five groups of IMID patients. The positive rate and titers of anti-S/RBD-IgG were significantly lower in patients receiving abatacept/rituximab therapy than in those receiving other DMARDs. All three SARS-CoV-2 vaccines showed acceptable safety profiles, and the common AEs were injection site reactions. We identified SLE as a significant predictor of increased autoimmunity and would like to promote awareness of the possibility of autoimmunity following vaccination.

COVID-19 vaccines: Considering sex differences in efficacy and safety

The development of SARS-CoV-2 vaccines represents a significant breakthrough for managing the COVID-19 pandemic. However, their approval process has exposed a crucial limitation in clinical trial reports-that is, a disregard for sex differences in response to vaccines. Historically, males and females have shown different reactions to vaccines of many kinds, which have become apparent with the arrival of COVID-19 vaccines in late-2020. In this article, we review regulatory data from Phase III vaccine trials as well as peer-reviewed reports from vaccines administered to the general population, many of which failed to stratify results by sex. We also discuss the exclusion of pregnant and lactating persons in drug development and the regulatory guidelines for use of COVID-19 vaccines in such populations. We conclude by proposing some questions to stimulate discussion with the intent of advancing the field toward precision medicine.

Reported Adverse Effects and Attitudes among Arab Populations Following COVID-19 Vaccination: A Large-Scale Multinational Study Implementing Machine Learning Tools in Predicting Post-Vaccination Adverse Effects Based on Predisposing Factors

Background: The unprecedented global spread of coronavirus disease 2019 (COVID-19) has imposed huge challenges on the healthcare facilities, and impacted every aspect of life. This has led to the development of several vaccines against COVID-19 within one year. This study aimed to assess the attitudes and the side effects among Arab communities after receiving a COVID-19 vaccine and use of machine learning (ML) tools to predict post-vaccination side effects based on predisposing factors. Methods: An online-based multinational survey was carried out via social media platforms from 14 June to 31 August 2021, targeting individuals who received at least one dose of a COVID-19 vaccine from 22 Arab countries. Descriptive statistics, correlation, and chi-square tests were used to analyze the data. Moreover, extensive ML tools were utilized to predict 30 post vaccination adverse effects and their severity based on 15 predisposing factors. The importance of distinct predisposing factors in predicting particular side effects was determined using global feature importance employing gradient boost as AutoML. Results: A total of 10,064 participants from 19 Arab countries were included in this study. Around 56% were female and 59% were aged from 20 to 39 years old. A high rate of vaccine hesitancy (51%) was reported among participants. Almost 88% of the participants were vaccinated with one of three COVID-19 vaccines, including Pfizer-BioNTech (52.8%), AstraZeneca (20.7%), and Sinopharm (14.2%). About 72% of participants experienced post-vaccination side effects. This study reports statistically significant associations (p < 0.01) between various predisposing factors and post-vaccinations side effects. In terms of predicting post-vaccination side effects, gradient boost, random forest, and XGBoost outperformed other ML methods. The most important predisposing factors for predicting certain side effects (i.e., tiredness, fever, headache, injection site pain and swelling, myalgia, and sleepiness and laziness) were revealed to be the number of doses, gender, type of vaccine, age, and hesitancy to receive a COVID-19 vaccine. Conclusions: The reported side effects following COVID-19 vaccination among Arab populations are usually non-life-threatening; flu-like symptoms and injection site pain. Certain predisposing factors have greater weight and importance as input data in predicting post-vaccination side effects. Based on the most significant input data, ML can also be used to predict these side effects; people with certain predicted side effects may require additional medical attention, or possibly hospitalization.

Testosterone in COVID-19: An Adversary Bane or Comrade Boon

COVID-19 is a pandemic disease caused by severe acute respiratory coronavirus 2 (SARS-CoV-2), which leads to pulmonary manifestations like acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In addition, COVID-19 may cause extra-pulmonary manifestation such as testicular injury. Both high and low levels of testosterone could affect the severity of COVID-19. Herein, there is substantial controversy regarding the potential role of testosterone in SARS-CoV-2 infection and COVID-19 severity. Therefore, the present study aimed to review and elucidate the assorted view of preponderance regarding the beneficial and harmful effects of testosterone in COVID-19. A related literature search in PubMed, Scopus, Web of Science, Google Scholar, and Science Direct was done. All published articles related to the role of testosterone and COVID-19 were included in this mini-review. The beneficial effects of testosterone in COVID-19 are through inhibition of pro-inflammatory cytokines, augmentation of anti-inflammatory cytokines, modulation of the immune response, attenuation of oxidative stress, and endothelial dysfunction. However, its harmful effects in COVID-19 are due to augmentation of transmembrane protease serine 2 (TMPRSS2), which is essential for cleaving and activating SARS-CoV-2 spike protein during acute SARS-CoV-2 infection. Most published studies illustrated that low testosterone levels are linked to COVID-19 severity. A low testosterone level in COVID-19 is mainly due to testicular injury, the primary source of testosterone.

Older adolescents and young adults willingness to receive the COVID-19 vaccine: Implications for informing public health strategies

Importance

The success in ending the COVID-19 pandemic rests partly on the mass uptake of the COVID-19 vaccine. Little work has been done to understand vaccine willingness among older adolescents and young adults. This is important since this age group may be less likely to adhere to public health guidelines.

Objective

To understand willingness of getting a vaccine and reasons for vaccine hesitancy among a sample of older adolescents and young adults.

Design

Data were from the Well-Being and Experiences study (The WE Study), a longitudinal community-based sample of older adolescents and young adults collected from Winnipeg, Manitoba, Canada from 2017 to 2020 (n = 664).

Setting

The study setting was a community-based observational longitudinal study.

Participants

Participants for the study were aged 14 to 17 years old at baseline in 2016–17 (n = 1000). Data were also collected on one parent/caregiver. Waves 2 (n = 747) and 3 (n = 664) were collected in 2019 and 2020, respectively.

Exposures

The main exposures were sociodemographic factors, health conditions, COVID-19 knowledge, and adversity history.

Main Outcomes

The main outcomes were COVID-19 vaccine willingness, hesitancy, and reasons for hesitancy.

Results

Willingness to get a COVID-19 vaccine was 65.4%. Willingness did not differ by age, sex, or mental health conditions, but did differ for other sociodemographic characteristics, physical health conditions, COVID-19 knowledge, practicing social/physical distancing, and adversity history. The most common reasons for not wanting a vaccine were related to safety, knowledge, and effectiveness. Sex differences were noted.

Conclusions and Relevance

Increasing uptake of the COVID-19 vaccine among older adolescents and young adults may rely on targeting individuals from households with lower income, financial burden, and adversity history, and generating public health messaging specifically aimed at vaccine safety, how it works to protect against illness, and why it is important to protect oneself against a COVID-19 infection.