Gam-COVID-Vac (Sputnik V) vaccine has no adverse effect on spermatogenesis in men

One of the most effective ways to prevent a new coronavirus infection SARS-CoV-2 is vaccination. The Gam-Covid-Vac vaccine containing a fragment of the SARS-CoV-2 genetic material was registered in 2020 [1]. Nowadays, people all over the world are vaccinated against the new coronavirus infection SARS-CoV-2, but the proportion of vaccinated people in different countries ranges from 75.6% (Malta) to 0.01% (Uganda). The proportion of the vaccinated population in Russia was 12.19% as of July 05, 2021 (https://yandex.ru/covid19/stat). Despite the confirmed high effectiveness of Gam-Covid-Vac in the prevention of severe forms of new coronavirus infection, a lot of men are concerned about the possible impact of vaccination on their reproductive health. Since vaccination may affect the development of autoimmune diseases involving gonads, the study of the influence of Gam-Covid-Vac on the reproductive health has been initiated [2–4].

For the entire period of vaccination, little data on the effect of various types of vaccines on human reproductive function has been collected in the literature [5–7]. Gam-Covid-Vac is a combined vector vaccine based on an adenovirus vector. Talotta et al. suggested in his study published in 2021 that vaccines based on adenovirus vectors can cause impaired regulation of the synthesis of type I interferons (IFN) [8]. Changes in the synthesis of type I IFN can theoretically lead to immuno-inflammatory rheumatic diseases, including systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS) and rheumatoid arthritis (RA) [9].

Bin Wang et al. (2017) performed a meta-analysis of 16 observational studies and found that vaccination increases the risk of developing SLE and RA [10]. Moreover, it was experimentally established that the administration of tetanus toxoid together with adjuvants in Th1 and Th2 prone mice was accompanied by the development of APS [11, 12]. The potential influence of vaccination on the development of immuno-inflammatory rheumatic diseases and consequently on the male reproductive health allows us to take a new look on the pathogenesis of autoimmune reactions developing in predisposed individuals in response to the introduction of adjuvant substances into the body (ASIA-syndrome). Currently, there are some studies on the effect of vaccination against coronavirus infection caused by SARS-CoV-2 on the male and female reproductive function (www.clinicaltrials.gov). The absence of a negative effect of vaccination on spermatogenesis in men has already been demonstrated in the results of the recent studies [13–15]. Therefore, the study of the effect of the vaccine against COVID-19 on the male reproductive function is of particular relevance. Due to the fact that among all Russian vaccines, only Gam-COVID-Vac (Sputnik V) has passed all the stages of clinical trials, it was chosen for studying the effect of vaccination on spermatogenesis in men [16].

The aim of the study was to evaluate the effect of the Gam-COVID-Vac (Sputnik V) vaccine on spermatogenesis, hormonal profile and the level of antiphospholipid antibodies in men.

Materials and methods

The prospective study included 45 men who were vaccinated against COVID-19 with Gam-COVID-Vac (Sputnik V). The criteria for inclusion in the study were the age from 18 to 55 years, normal or subnormal parameters of the spermogram before vaccination, the absence of a previous history of COVID-19, a negative RT-PCR result in SARS-CoV-2 testing, negative SARS-CoV-2 IgG results prior to vaccination. The criteria for non-inclusion were contraindications to vaccination according to the instructions, oncological diseases of any localization, rheumatic and autoimmune diseases, tuberculosis, chronic systemic infections, a history of allergic diseases, hormone therapy and any vaccination carried out 30 days before inclusion in the study, treatment with immunoglobulins and immunomodulatory drugs 3 months before inclusion in the study. The exclusion criteria were COVID-19 during the vaccination period, a severe undesirable reaction resulting in the cancelled 2nd dose of the vaccine, and the patient’s refusal to continue vaccination.

The concentration of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and total testosterone was determined in blood serum with an electrochemiluminescent method on an automatic immunochemical analyzer “Cobas e411” (Roche Diagnostics GmbH, Germany) using commercial kits from this manufacturer. The concentration of thyroid-stimulating hormone (TSH) was determined in blood serum using an immunochemiluminescent method on an automatic immunochemical analyzer “IMMULITE 2000” (Siemens, USA). The analysis of blood for IgM and IgG antiphospholipid antibodies (aPL) to cardiolipin (aCL), β2-glycoprotein-1 (aß2-GP1), annexin V (aAnV), phosphatidylserine (aPS) was carried out with enzyme immunoassay using “ORGENTEC Diagnostika” kits (Germany). Also, IgG antibodies to SARS-CoV-2 in blood serum were determined with enzyme immunoassay using the test system “A set of reagents for detecting IgG specific to SARS-CoV-2 spike using enzyme immunoassay” (RPC “Diagnostic Systems”, Russia). The results were assessed using spectrophotometer “Infinite F50” (TECAN, USA).

According to the WHO laboratory manual [17], reference values of ejaculate parameters were used for evaluating sperm pathology (Table 1).

Sperm pathology had the following criteria:

• oligozoospermia characterized by a decrease in the concentration of spermatozoa <15 mln/ml;
• asthenozoospermia characterized by a decrease in sperm motility below normal values (total motility <40%, spermatozoa with progressive movement <32%);
• teratozoospermia characterized by an increase in the number of spermatozoa with abnormal morphology (96%).

Additionally, the number of IgG antisperm antibodies was determined using latex particles on the surface of spermatozoa (norm ≤ 50%); DNA fragmentation of spermatozoa was identified using the TUNEL method (norm <15%).

Statistical analysis

The statistical software package Statistica 10 (USA) was used for statistical analysis. The data were represented as absolute values and % for categorical data, medians (with an interquartile interval) for quantitative data. Medians were compared using pairwise testing methods, namely, paired Wilcoxon test for related samples due to the abnormal distribution of data for all values. Normal distribution of the data was evaluated using the Shapiro–Wilk criterion. The correlation was analyzed using Spearman’s criterion. The differences between the statistical values were considered statistically significant at р˂0.05.

The study was approved by the Local Ethics Committee of the Academician V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia.

Results

The average age of the men was 36.0 (30.0–44.0) years, the body mass index (BMI) was 25.9 (23.5–28.7) kg/m2. The assessment of clinical and anamnestic data revealed that the morbidity of patients was low: bronchial asthma was noted in 2 patients (4.4%), arterial hypertension – in 1 (2.2%), chronic tonsillitis – in 2 (4.4%), chronic gastritis – in 3 (6.7%), chronic prostatitis – in 3 (6.7%), pollinosis – in 3 men (6.7%).

The vaccine was generally well tolerated by the patients, there were no serious adverse events associated with the injection of the vaccine. The reaction to the vaccine was more frequently observed after injecting the 2nd dose and was short-term (1–2 days). Local reaction at the injection site was observed in 7 patients (15.5%), subfebrile temperature was noted in 43 (95.5%), intoxication symptoms such as headache and/or myalgia were observed in 13 cases (28.9%).

SARS-CoV-2 IgG antibodies were detected in almost all vaccinated patients, only in 3 (6.7%) patients their level did not reach the threshold value for positivity.

The comparison of the average parameters of the spermogram before and after vaccination did not reveal significant differences, including the level of MAR IgG and DNA fragmentation of spermatozoa (Table 2).

The analysis of the dynamics of the spermogram parameters before and after vaccination in men with pathospermia (n=17) compared to men with normospermia (n=28) did not reveal a significant difference. The delta of sperm concentration in 1 ml of ejaculate in patients with pathospermia was 0.5 (-19.0–8.7), in patients with normospermia – 7.0 (-11.0–29.0) (p>0.05). The delta of total sperm motility in patients with pathospermia was –3.0 (-5.0–1.0)%, in patients with normospermia –3.0 (-5.0–1.0)% (p>0.05). The delta of the number of normal sperm forms in patients with pathospermia was 0.0 (0.0–0.0), with normospermia – 0.0 (0.0–0.0) (p>0.05). Leukocytospermia with a white blood cell concentration of more than 1 million/ml was not revealed in any patient either before or after vaccination. The comparison of the average parameters of the patient’s hormonal profile before and after vaccination did not show any significant differences in the parameters (Table 3).

The level of aPL was subsequently analyzed before and after vaccination (Figure). There was a slight decrease in the level of aß2-GP1 IgG, aCL IgM and aPS IgG after vaccination compared to the baseline values. The level of aPL did not exceed the reference values in all patients.

There was a correlation analysis of the dependence of changes in the parameters of the spermogram (total sperm number, total sperm motility, viability, percentage of morphologically normal forms, percentage of progressively mobile forms) and IgM and IgG aPL to aCL, aß2-GP1, aAnV and aPS. The results of this analysis did not reveal any significant correlations (r<0.20, p>0.05). The vaccine has no effect on spermatogenesis in men, but there is evidence of a negative effect of COVID-19 on the male reproductive function. The analysis revealed a wide representation of receptors for SARS-CoV-2 (angiotensin-converting enzyme (ACE2), transmembrane serine protease 2 (TMPRSS2), CD147 (basigin) in human reproductive organs and tissues [18–22]. It should be emphasized that spike protein of SARS-CoV-2 binds to the ACE2 receptor contributing to the penetration of the virus into the target cell [23]. The study of Haghpanah A. et al. showed that the penetration of the SARS-CoV-2 virus into spermatogonia, Leydig cells, as well as Sertoli cells can lead to the changes in the level of sex hormones, increased DNA fragmentation, and decreased sperm motility [24]. The results of other studies confirm the negative impact of COVID-19 on spermatogenesis [25] and hormonal profile of men [26]. It cannot be excluded that the interaction of the SARS-CoV-2 virus with the ACE2 receptor can initiate the development of specific epididymo-orchitis due to the development of systemic vasculitis [27, 28].

Conclusion

This is one of the first studies that has revealed the effect of the Gam-COVID-Vac vaccine on spermatogenesis, hormonal profile and aPL level in men. All patients included in the study initially had normal or subnormal spermogram parameters and did not experience any severe somatic diseases. Factors that could influence the excessive autoimmune response were also excluded from the study.

According to the preliminary data of the study, Gam-COVID-Vac does not have a negative effect on spermatogenesis and hormonal profile in men, including men with moderate pathospermia (oligoasteno- and/or teratozoospermia). Moreover, vaccination does not cause an increase in the level of aPL, as well as antisperm antibodies (MAR), which may indirectly be indicative of the absence of changes in the reproductive function of autoimmune genesis under the influence of the vaccine. The research will continue and further study will include 200 men.