Future Vaccination Efforts Research Articles

A path forward for Staphylococcus aureus vaccine development.

The pursuit of a vaccine to quell Staphylococcus aureus disease has been unfruitful. In this Viewpoint, we explore the biological linkage between microbial niche acquisition and host immunity as a basis to guide future vaccine efforts.

Intranasal Self-Adjuvanted Lipopeptide Vaccines Elicit High Antibody Titers and Strong Cellular Responses against SARS-CoV-2.

Despite concerted efforts to tackle the COVID-19 pandemic, the persistent transmission of SARS-CoV-2 demands continued research into novel vaccination strategies to combat the virus. In light of this, intranasally administered peptide vaccines, particularly those conjugated to an immune adjuvant to afford so-called "self-adjuvanted vaccines", remain underexplored. Here, we describe the synthesis and immunological evaluation of self-adjuvanting peptide vaccines derived from epitopes of the spike glycoprotein of SARS-CoV-2 covalently fused to the potent adjuvant, Pam2Cys, that targets toll-like receptor 2 (TLR2). When administered intranasally, these vaccines elicited a strong antigen-specific CD4+ and CD8+ T-cell response in the lungs as well as high titers of IgG and IgA specific to the native spike protein of SARS-CoV-2. Unfortunately, serum and lung fluid from mice immunized with these vaccines failed to inhibit viral entry in spike-expressing pseudovirus assays. Following this, we designed and synthesized fusion vaccines composed of the T-cell epitope discovered in this work, covalently fused to epitopes of the receptor-binding domain of the spike protein reported to be neutralizing. While antibodies elicited against these fusion vaccines were not neutralizing, the T-cell epitope retained its ability to stimulate strong antigen-specific CD4+ lymphocyte responses within the lungs. Given the Spike(883-909) region is still completely conserved in SARS-CoV-2 variants of concern and variants of interest, we envision the self-adjuvanting vaccine platform reported here may inform future vaccine efforts.

Immune gene expression changes more during a malaria transmission season than between consecutive seasons.

Our work seeks to understand how the immune response to Plasmodium falciparum malaria changes between infections that occur during low and high malaria transmission seasons, and highlights that immune gene expression changes more during the high transmission season. This provides important insight into the dynamics of the anti-malarial immune response that are important to characterize over these short time frames to better understand how to exploit this immune response with future vaccine efforts.

A qualitative examination of the experiences and perspectives of interprofessional primary health care teams in the distribution of the COVID-19 vaccination in Ontario, Canada.

Primary health care (PHC) teams contributed to all phases of the COVID-19 vaccination distribution. However, there has been criticism for not fully utilizing the expertise and infrastructure of PHC teams for vaccination distribution. Our study sought to understand the role PHC teams had in the distribution of the COVID-19 vaccine in Ontario, Canada. The key objective informing this study was to explore the experiences and perspectives of interprofessional PHC teams in the distribution of COVID-19 vaccination across Ontario. A qualitative approach was used for this study, which involved 39 participants from the six health regions of the province. Eight focus groups were conducted with a range of interprofessional healthcare providers, administrators, and staff working in PHC teams across Ontario. The sample reflected a diverse range of clinical, administrative, and leadership roles in PHC. Focus groups were audio-recorded and transcribed, while transcriptions were then analyzed using thematic analysis. We identified the following four themes in the data: i) PHC teams know their patients; ii) mobilizing team capacity for vaccination, iii) intersectoral collaborations, and iv) operational challenges. PHC teams were an instrumental component in supporting COVID-19 vaccinations in Ontario. The involvement of PHC in future vaccination efforts is key but requires additional resourcing and inclusion of PHC in decision-making. This will ensure provider well-being and maintain collaborations established during COVID-19 vaccination.

Exploring the impacts of neighborhood disadvantage on Medicare beneficiaries’ early COVID-19 vaccine uptake

A variety of factors influenced the American public's experiences with the COVID-19 pandemic and initial availability and uptake of COVID-19 vaccines. To examine variation in early COVID-19 vaccine uptake based on neighborhood disadvantage along with individual sociodemographic and health characteristics, we used Spring 2021 data from the Medicare Current Beneficiary Survey (MCBS), a nationally representative, longitudinal survey of the Medicare population conducted by the Centers for Medicare & Medicaid Services. Bivariate analyses showed that beneficiaries in disadvantaged neighborhoods were less likely to have received at least one vaccine dose than those in less disadvantaged neighborhoods (49.7%, SE = 1.6 versus 66.6%, SE = 1.0, p < 0.0001). After accounting for individual characteristics, the relationship between neighborhood disadvantage and vaccine uptake was not statistically significant. However, interaction effects of neighborhood disadvantage by urbanicity showed a more complex picture, where those in disadvantaged urban areas had the lowest odds of vaccine uptake (p < 0.01). The relationship between neighborhood disadvantage and vaccination is multifaceted, requiring further research to inform future vaccination efforts targeting the most vulnerable beneficiaries.

COVID-19 Vaccinations, Trust, and Vaccination Decisions within the Refugee Community of Calgary, Canada.

Refugee decisions to vaccinate for COVID-19 are a complex interplay of factors which include individual perceptions, access barriers, trust, and COVID-19 specific factors, which contribute to lower vaccine uptake. To address this, the WHO calls for localized solutions to increase COVID-19 vaccine uptake for refugees and evidence to inform future vaccination efforts. However, limited evidence engages directly with refugees about their experiences with COVID-19 vaccinations. To address this gap, researchers conducted qualitative interviews (N = 61) with refugees (n = 45), sponsors of refugees (n = 3), and key informants (n = 13) connected to local COVID-19 vaccination efforts for refugees in Calgary. Thematic analysis was conducted to synthesize themes related to vaccine perspectives, vaccination experiences, and patient intersections with policies and systems. Findings reveal that refugees benefit from ample services that are delivered at various stages, that are not solely related to vaccinations, and which create multiple positive touch points with health and immigration systems. This builds trust and vaccine confidence and promotes COVID-19 vaccine uptake. Despite multiple factors affecting vaccination decisions, a key reason for vaccination was timely and credible information delivered through trusted intermediaries and in an environment that addressed refugee needs and concerns. As refugees placed trust and relationships at the core of decision-making and vaccination, it is recommended that healthcare systems work through trust and relationships to reach refugees. This can be targeted through culturally responsive healthcare delivery that meets patients where they are, including barrier reduction measures such as translation and on-site vaccinations, and educational and outreach partnerships with private groups, community organizations and leaders.

Predictors of Human Papillomavirus Vaccine Intention and Uptake Among US Hispanic Parents: A Cross-Sectional Study.

Introduction: This study explored the influence of the Theory of Planned Behavior constructs on human papillomavirus (HPV) vaccine (HPVV) intentions and uptake among Hispanic parents in South Florida for their children aged 9-21. Method: A descriptive exploratory analysis was conducted using 39 surveys completed by Hispanic parents. These surveys encompassed demographic data and questions about HPVV uptake, intention, attitudes, subjective norms, knowledge, self-efficacy, and awareness. Results: Most participants were uninsured (77%), unemployed (59%), and had low Americanism acculturation (74%). A little over half were aware of the HPVV (54%), yet most had high positive HPVV attitudes (95%) and self-efficacy (85%). HPVV intentions within the year were also high (82%); however, HPVV uptake (45%) and HPVV knowledge (40%) were low at the time of the study. Most parents reported physicians (72%) and nurses/nurse practitioners (59%) as the most influential individuals in their decision-making. A statistically significant relationship between HPVV intention and HPVV attitude (X_Wald^2 (1) = 5.71, p = 0.02., OR = 5.11) and between HPVV uptake and HPVV awareness (X_Wald^2 (1) = 4.63, p = 0.03., OR = 12) were observed. Conclusion: This study recommends further research and targeted interventions to improve HPVV awareness among Hispanic communities. The participants' highly positive attitudes and self-efficacy provide a hopeful outlook for future vaccination efforts within this demographic.

How can early COVID-19 vaccine campaigns in the US-affiliated Pacific Islands inform future vaccine efforts: a cross-sectional analysis

IntroductionThe US-affiliated Pacific Islands (USAPI) are six geographically isolated and culturally distinct Pacific Island jurisdictions with special relationships with the USA; the USAPI were included in the US COVID-19 vaccination...

Understanding COVID-19 vaccine hesitancy in Canada

While Canada has had relatively high vaccination rates against COVID-19, specifically during earlier waves of the pandemic, vaccine hesitancy has continued to serve as a significant barrier to adequate protection against the virus and, more recently, booster vaccine uptake. This paper explores the processes underlying Canadians’ perceptions of COVID-19 vaccines and their decisions to take or refuse them, as well as how public policy and health messaging about vaccination has influenced vaccination attitudes and behaviors. Our focus group interviews with 18 vaccinated and unvaccinated adult Canadians conducted during October 2021 reveal that, in some respects, COVID-19 vaccine hesitancy conforms to prior knowledge about some of the factors that affect vaccine attitudes (e.g., the influence of known medical providers) but deviates from current theoretical frameworks regarding general vaccine hesitancy. Specifically, these frameworks emphasize a lack of scientific knowledge and literacy (“knowledge deficit” accounts) or individuals’ inability to incorporate rational risk perceptions into initial emotional responses to vaccines (“emotionality/irrationality” accounts). In contrast to the knowledge deficit account, we find that expressions of COVID-19 vaccine hesitancy were most frequently associated with an information surplus or inability to prioritize information from multiple and often contradictory sources. Furthermore, top-down pro-vaccination messaging often triggered significant pushback against what participants perceived as moral shaming of the unvaccinated. Our findings demonstrate the necessity for a new framework to understand and address vaccine hesitancy. A better theoretical account of vaccine hesitancy has important implications for future vaccination efforts, specifically within the context of new variants and low booster vaccination rates in Canada.

An atlas of continuous adaptive evolution in endemic human viruses

Through antigenic evolution, viruses such as seasonal influenza evade recognition by neutralizing antibodies. This means that a person with antibodies well tuned to an initial infection will not be protected against the same virus years later and that vaccine-mediated protection will decay. To expand our understanding of which endemic human viruses evolve in this fashion, we assess adaptive evolution across the genome of 28 endemic viruses spanning a wide range of viral families and transmission modes. Surface proteins consistently show the highest rates of adaptation, and ten viruses in this panel are estimated to undergo antigenic evolution to selectively fix mutations that enable the escape of prior immunity. Thus, antibody evasion is not an uncommon evolutionary strategy among human viruses, and monitoring this evolution will inform future vaccine efforts. Additionally, by comparing overall amino acid substitution rates, we show that SARS-CoV-2 is accumulating protein-coding changes at substantially faster rates than endemic viruses.

Novel Psychosocial Correlates of COVID-19 Vaccine Hesitancy: Cross-Sectional Survey.

Effective COVID-19 vaccines have been available since early 2021 yet many Americans refuse or delayed uptake. As of mid-2022, still around 30% of US adults remain unvaccinated against COVID-19. The majority (81%) of these unvaccinated adults say they will "definitely not" be getting the COVID-19 vaccine. Understanding the determinants of COVID-19 vaccine uptake is critical to reducing death and illness from the virus, as well as to inform future vaccine efforts, such as the more recent bivalent (omicron) booster. This study aimed to expand our understanding of psychosocial determinants of COVID-19 vaccine uptake. We focus on both COVID-19-specific factors, such as COVID-19 conspiracy beliefs, as well as more global personality attributes such as dogmatism, reactance, gender roles, political beliefs, and religiosity. We conducted a web-based survey in mid-2021 of a representative sample of 1376 adults measuring both COVID-19-specific beliefs and attitudes, as well as global personality attributes. COVID-19 vaccination status is reported at 3 levels: vaccinated; unvaccinated-may-get-it; unvaccinated-hard-no. Our analyses focused on the correlation of COVID-19 vaccination status with 10 psychosocial attributes: COVID-19-specific conspiracy theory beliefs; COVID-19 vaccine misinformation; COVID-19-related Rapture beliefs; general antivaccination beliefs; trait reactance; trait dogmatism; belief in 2020 election fraud; belief in a QAnon conspiracy; health care system distrust; and identification with traditional gender roles. We used a multivariate analysis of covariance to examine mean differences across vaccine status groups for each of the correlates while holding constant the effects of age, gender, race, income, education, political party, and Evangelicalism. Across the 10 psychosocial correlates, several different response scales were used. To allow for comparison of effects across correlates, measures of effect size were computed by converting correlates to z scores and then examining adjusted mean differences in z scores between the groups. We found that all 10 psychosocial variables were significantly associated with vaccination status. After general antivaccination beliefs, COVID-19 misinformation beliefs and COVID-19 conspiracy beliefs had the largest effect on vaccine uptake. The association of these psychosocial factors with COVID-19 vaccine hesitancy may help explain why vaccine uptake has not shifted much among the unvaccinated-hard-no group since vaccines became available. These findings deepen our understanding of those who remain resistant to getting vaccinated and can guide more effective tailored communications to reach them. Health communication professionals may apply lessons learned from countering related beliefs and personality attributes around issues such as climate change and other forms of vaccine hesitancy. For example, using motivational interviewing strategies that are equipped to handle resistance and provide correct information in a delicate manner that avoids reactance.

“They'll take a gun to me before I get that shot”: Rationalization, emotions, and misinformation in COVID‐19 vaccine hesitancy

AbstractVaccine hesitancy—the reluctance, delay, or refusal to vaccinate regardless of availability—is not a new concept in psychology, medicine, or public health. However, given the emotions surrounding the COVID‐19 vaccine, hesitancy has proven difficult to overcome. To‐date, the bulk of available data on vaccine hesitancy are quantitative, leaving room for exploratory investigations into the reasons adults remain unvaccinated. This qualitative study assessed the motivations, beliefs, and perceptions of individuals who have decided to remain unvaccinated against COVID‐19. We had one exploratory research question: What social psychological justifications emerge from vaccine hesitant people's explanations of their decisions to remain unvaccinated? To assess this question, we conducted 18 interviews with unvaccinated adults throughout 2021–2022. The interviews consisted of 20 questions regarding participants' perceptions of the COVID‐19 vaccine and their intentions to get vaccinated. Thematic analysis revealed four main themes in the answers provided by participants: rationalization; identity, beliefs and potential modifiers; emotional responses; and information sources. These results offer insight for future vaccination efforts.

Achieving COVID‐19 herd immunity in Bangladesh

AbstractAchieving herd immunity against COVID‐19 through vaccination is a global target, including in lower resource settings. Despite the challenges and limitations, Bangladesh has achieved its target of vaccinating 70% of its population, with good vaccine coverage among refugees, remote population, and women. This can be attributed to the evidence‐informed adaptability and collaborative approaches of the program. Yet some challenges remain, including dependence on donors and the need to ramp up vaccination among the underserved communities. This article discusses the factors contributing to the achievements of the COVID‐19 vaccination program of Bangladesh and the remaining challenges that should be addressed by the government to ensure the sustainability of the program and inform future vaccination efforts.

The effect of neutrophils on limited hepatitis C virus vaccine immunogenicity in people who inject drugs

Abstract In the only efficacy trial of a hepatitis C virus (HCV) vaccine, the vector-based vaccine lowered peak HCV RNA levels in people who inject drugs (PWIDs) but did not prevent chronic HCV infection. The same vaccine regimen tested in healthy controls (HCs) resulted in a larger percentage of individuals responding to vaccination (100 vs. 78%) and a 3-fold higher magnitude of T cell responses compared to PWIDs. We evaluated baseline immune characteristics of PWIDs to understand the reduced responses, ruling out differences in baseline anti-vector immunity, subclinical HCV exposure, and increased T regs. However, we found markedly elevated neutrophil counts in PWIDs at baseline compared to HCs. Elevated neutrophils were previously linked to nonresponse to hepatitis B vaccination in HCs, yet this phenomenon has been largely understudied. We analyzed baseline neutrophil phenotypes using flow cytometry and identified elevated PD-L1, CD11b, and CD63 on neutrophils from PWIDs compared to HCs. Stimulation of HC neutrophils with opioid receptor (OR) agonist DAMGO significantly upregulated PD-L1 and CD11b, an effect partially reversed with an OR antagonist. We also observed metabolic reprogramming of neutrophils in PWIDs compared to HCs, with higher expression of glycolytic machinery (GLUT1/HK2) and mitochondrial membrane protein VDAC1, indicative of increased mitochondrial mass and use of oxidative phosphorylation. Elevated baseline CD11b and CD63 suggest dysregulation and activation of neutrophils, with increased PD-L1 potentially contributing to poor T cell responses in PWIDs. Mechanistic studies of dysregulated neutrophil interactions with T cells may provide insights into vaccine-induced responses and future vaccine efforts. Supported by NIH grant U19 AI159822.

Reaching late adopters: factors influencing COVID-19 vaccination of Marshallese and Hispanic adults

BackgroundMarshallese and Hispanic communities in the United States have been disproportionately affected by COVID-19. Identifying strategies to reach late vaccine adopters is critical for ongoing and future vaccination efforts. We utilized a community-engaged approach that leveraged an existing community-based participatory research collaborative of an academic healthcare organization and Marshallese and Hispanic faith-based organizations (FBO) to host vaccination events.MethodsBilingual Marshallese and Hispanic study staff conducted informal interviews with 55 participants during the 15-minute post-vaccination observation period and formal semi-structured interviews with Marshallese (n = 5) and Hispanic (n = 4) adults post-event to assess the implementation of community vaccine events at FBOs, with a focus on factors associated with the decision to attend and be vaccinated. Formal interview transcripts were analyzed using thematic template coding categorized with the socio-ecological model (SEM). Informal interview notes were coded via rapid content analysis and used for data triangulation.ResultsParticipants discussed similar factors influencing attitudes and behaviors toward receiving the COVID-19 vaccine. Themes included: (1) intrapersonal – myths and misconceptions, (2) interpersonal – protecting family and family decision-making, (3) community – trust of community location of events and influence of FBO members and leaders, (4) institutional – trust in a healthcare organization and bilingual staff, and (5) policy. Participants noted the advantages of vaccination delivery at FBOs, contributing to their decision to attend and get vaccinated.ConclusionsThe following strategies may improve vaccine-related attitudes and behaviors of Marshallese and Hispanic communities not only for the COVID-19 vaccine but also for other preventive vaccinations: 1) interpersonal-level – develop culturally-focused vaccine campaigns targeting the family units, 2) community-level – host vaccination events at convenient and/or trusted locations, such as FBOs, and engage community and/or FBO formal or lay leaders as vaccine ambassadors or champions, and 3) institutional-level – foster trust and a long-term relationship with the healthcare organization and provide bilingual staff at vaccination events. Future research would be beneficial to investigate the effects of replicating these strategies to support vaccine uptake among Marshallese and Hispanic communities.

CD193 (CCR3) expression by B cells correlates with reduced IgE production in paediatric schistosomiasis.

We demonstrate that CD193, the eotaxin receptor, is highly expressed on circulating B cells in paediatric schistosomiasis mansoni. CD193 plays a role in directing granulocytes into sites of allergic-like inflammation in the mucosa, but little is known about its functional significance on human B cells. We sought to characterize CD193 expression and its relationship with S. mansoni infection. We found that CD193+ B cells increased with the intensity of schistosome infection. In addition, a significant negative association was observed between CD193 expression by B cells and IgE production. Decreased IgE levels are generally associated with susceptibility to re-infection. B cell stimulation with eotaxin-1 increased CD193 levels whereas IL-4 led to a reduction. This was supported by plasma levels of eotaxin-1 correlating with CD193 levels on B cells and other cells. In contrast, CD193 expression was induced on naive B cells with a combination of IL-10 and schistosome antigens. Whereas T cells had a modest increase in CD193 expression, only B cell CD193 appeared functionally chemotactic to eotaxin-1. Thus, CD193+ B cells, which co-express CXCR5, may be enroute to sites with allergic-like inflammation, such as gastrointestinal follicles, or even to Th2 granulomas, which develop around parasite eggs. Overall, our results suggest that schistosome infection may promote CD193 expression and suppress IgE via IL-10 and other undefined mechanisms related to B cell trafficking. This study adds to our understanding of why young children may have poor immunity. Nonetheless, praziquantel treatment was shown to reduce percentages of circulating CD193+ B cells lending hope for future vaccine efforts.

Comparison of COVID-19 Vaccination Rollout Approaches across Canada: Case Studies of Four Diverse Provinces

Across Canada, there were notable differences in the rollout of provincial/territorial COVID-19 vaccination programs, reflecting diverse sociodemographic profiles, geopolitical landscapes, health system designs, and pandemic experiences. We collected information regarding underlying principles and goals, governance and authority, transparency and diversity of communications, activities to strengthen infrastructure and workforce capacity, and entitlement and access in four diverse provinces (British Columbia, Saskatchewan, Ontario, Nova Scotia). Through cross-case analysis, we observed significant differences in provincial rollouts of the primary two-dose vaccination series in adults between December 2020 and December 2021. Nova Scotia was the only province to state explicit coverage goals and adhere to plans tying coverage to the relaxation of public health measures. Both Nova Scotia and British Columbia implemented fully centralized vaccination booking systems. In contrast, Saskatchewan's initial highly centralized approach enabled the rapid delivery of first doses; however, rollout of second doses was slower and more decentralized, occurring primarily through community pharmacies. In alignment with its decentralized health system, Ontario pursued a regionalized approach, primarily led by its existing public health unit network. Our research suggests explicit goals, centralized booking, and flexible delivery strategies improved uptake; however, ongoing learning will be crucial for informing the success of future vaccination efforts.

DISCUSSING AND DELIVERING THE COVID-19 VACCINE: EXPERIENCES IN VA'S HOME BASED PRIMARY CARE PROGRAM

Abstract COVID-19 vaccines represented a new type of vaccination with specific logistical challenges for distribution and administration. As the Department of Veterans Affairs (VA) embarked on a campaign to vaccinate its Veterans, homebound Veterans presented unique challenges. Therefore, we studied how VA’s Home Based Primary Care (HBPC) teams vaccinated Veterans to inform best practices for future vaccination efforts for similar vulnerable populations. From March-May 2021, we fielded a survey to HBPC staff at 145 VA programs nationally, gathering insights from 73 teams. Findings highlighted the importance of vaccine communication and education; the need to prioritize HBPC Veterans receiving vaccines; ironing out vaccine distribution and administration logistics; and that internal and external structures were required to safely vaccinate Veterans in-home.

Modeling a COVID-19 Vaccination Campaign in the State of Madhya Pradesh, India

COVID-19 vaccination campaigns have been launched across the globe to mitigate the impact of the COVID-19 disease. However, COVID-19 vaccination campaigns (Vaccination campaigns are the complete process of COVID-19 vaccination campaigns beyond just administrating vaccines.) are a complex multi-stakeholder process, and therefore, it is important to understand the key components and drivers of vaccination campaigns to help devise strategies to increase vaccination coverage for existing and future vaccination efforts. A system dynamics modeling approach was used to trace the vaccination campaign for the Indian state of Madhya Pradesh. The results identified the key stakeholders of the vaccination campaign and their inter-linkages, and the diverse perspectives of stakeholders of vaccination campaigns in Madhya Pradesh were collated in a structured format. Further, system dynamics models were developed to capture all aspects of the vaccination campaign in Madhya Pradesh, including the challenges and innovations. The outcomes of the study can assist academicians, practitioners, and policymakers develop vaccination programs at sub-national, national, and global levels. They will guide decision-makers to take preemptive measures to mitigate possible risks and challenges and provide improved services as part of vaccination campaigns.

Effects of inactivated SARS-CoV-2 vaccination on male fertility: A retrospective cohort study.

Numerous studies have revealed severe damage to male fertility from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, raising concerns about the potential adverse impact on reproductive function of the coronavirus disease 2019 (COVID-19) vaccine developed based on the virus. Interestingly, there are several researchers who have studied the impact of the COVID-19 mRNA vaccine since then but have come up with conflicting results. As a near-ideal candidate for mass immunization programs, inactivated SARS-CoV-2 vaccine has been widely used in many countries, particularly in less wealthy nations. However, little is known about its effect on male fertility.Here, we conducted a retrospective cohort study at a single large center for reproductive medicine in China between December 2021 and August 2022. Five hundred and nineteenfertile men with no history of laboratory-confirmed COVID-19 were included and categorized into four groups based on their vaccination status: unvaccinated group (n = 168), one-dose vaccinated group (n = 8), fully vaccinated group (n = 183), and booster group (n = 160). All of them underwent a semen analysis and most had serum sex hormone levels tested.There were no significant differences in all semen parameters and sex hormone levels between the unvaccinated group and either vaccinated group. To account for possible vaccination-to-test interval-specific changes, sub-analyses were performed for two interval groups: ≤90 and >90 days. As expected, most of the semen parameters and sex hormone levels remained unchanged between the control and vaccinated groups. However, participants in vaccinated group (≤90 days) have decreased total sperm motility and increased follicle-stimulating hormonelevel compared with the ones in unvaccinated group. Moreover, some trends similar to those found during COVID-19 infection and recovery were observed in our study. Fortunately, all values are within the normal range. In addition, vaccinated participants reported few adverse reactions. No special medical intervention was required, and no serious adverse reactions happened.Our study suggests that inactivated SARS-CoV-2 vaccination does not impair male fertility, possibly due to the low frequency of adverse effects. This information reassures young male population who got this vaccine worldwide, and helps guide future vaccination efforts.