Prevalence of Anti-SARS-CoV-2 Antibodies in Poznań, Poland, after the First Wave of the COVID-19 Pandemic

Vaccination against the SARS-CoV-2 virus in patients undergoing Hymenoptera venom immunotherapy

Introduction

The SARS-CoV-2 epidemic has unquestionably left a significant mark on the global healthcare system. Implementation of the commonly available vaccinations against COVID-19 is intended to reduce the risk of a severe course of the disease. Due to a very brief development period of the new vaccines, concerns have appeared among the public with regard to the possible adverse effects of the newly-developed preparations, as well as to the risks of causing allergic reactions. Regular medical observation during the Hymenoptera venom immunotherapy provides significant possibilities to note any potential adverse effects of vaccines against COVID-19, as well as of complications of an experienced SARS CoV-2 infection.

Aim

To assess the issues connected with vaccination against COVID-19, complications following vaccination, as well as incidence and course of the disease among patients undergoing venom immunotherapy (VIT) due to an allergy to Hymenoptera venom.

Material and methods

We investigated 37 persons aged 19 to 70 (20 women; 17 men) undergoing Hymenoptera venom immunotherapy in our department.

Results

21.6% have experienced an infection with the SARS-CoV-2 virus, confirmed by a diagnostic test. No person participating in the study had experienced a severe infection which would require hospitalization. Elderly people have been vaccinated statistically significantly more often than young people.

Conclusions

The risk related to vaccination in this group of patients does not seem to be higher than in the general population.

Influenza vaccination as a prognostic factor of humoral IgA responses to SARS-CoV-2 infection

There is evidence that influenza vaccination may provide additional benefits by inducing training of innate immunity and increasing humoral responses to heterologous challenges. Immunoglobulin A (IgA) antibodies dominate the early phase of the adaptive response to SARS-CoV-2 infection, but whether their production may be associated with previous influenza vaccination has not been a subject of any study. This study compared serum SARS-CoV-2-specific IgA responses, measured with Microblot-Array assay, in individuals who experienced COVID-19 (N = 1318) and differed in the status of the seasonal influenza vaccine, age, sex, and disease severity. Influenza-vaccinated individuals had a higher seroprevalence of IgA antibodies against nucleocapsid (anti-NP; by 10.1%), receptor-binding domain of spike protein (anti-RBD; by 11.8%) and the S2 subunit of spike protein (anti-S2; by 6.8%). Multivariate analysis, including age, sex, and COVID-19 severity, confirmed that receiving the influenza vaccine was associated with higher odds of being seropositive for anti-NP (OR, 95% CI = 1.57, 1.2-2.0), anti-RBD (OR, 95% CI = 1.6, 1.3-2.0), and anti-S2 (OR, 95% CI = 1.9, 1.4-2.7), as well as being seropositive for at least one anti-SARS-CoV-2 IgA antibody (OR, 95% CI = 1.7, 1.3-2.1) and all three of them (OR, 95% CI = 2.6, 1.7-4.0). Age ≥ 50 years was an additional factor predicting better IgA responses. However, the concentration of particular antibodies in seropositive subjects did not differ in relation to the influenza vaccination status. The study evidenced that influenza vaccination was associated with improved serum IgA levels produced in response to SARS-CoV-2 infection. Further studies are necessary to assess whether trained immunity is involved in the observed phenomenon.

Influence of the Demographic, Social, and Environmental Factors on the COVID-19 Pandemic-Analysis of the Local Variations Using Geographically Weighted Regression

As the COVID-19 pandemic continues, an increasing number of different research studies focusing on various aspects of the pandemic are emerging. Most of the studies focus on the medical aspects of the pandemic, as well as on the impact of COVID-19 on various areas of life; less emphasis is put on analyzing the influence of socio-environmental factors on the spread of the pandemic. In this paper, using the geographically weighted regression method, the extent to which demographic, social, and environmental factors explain the number of cases of SARS-CoV-2 is explored. The research was performed for the case-study area of Poland, considering the administrative division of the country into counties. The results showed that the demographic factors best explained the number of cases of SARS-CoV-2; the social factors explained it to a medium degree; and the environmental factors explained it to the lowest degree. Urban population and the associated higher amount and intensity of human contact are the most influential factors in the development of the COVID-19 pandemic. The analysis of the factors related to the areas burdened by social problems resulting primarily from the economic exclusion revealed that poverty-burdened areas are highly vulnerable to the development of the COVID-19 pandemic. Using maps of the local R² it was possible to visualize how the relationships between the explanatory variables (for this research-demographic, social, and environmental factors) and the dependent variable (number of cases of SARS-CoV-2) vary across the study area. Through the GWR method, counties were identified as particularly vulnerable to the pandemic because of the problem of economic exclusion. Considering that the COVID-19 pandemic is still ongoing, the results obtained may be useful for local authorities in developing strategies to counter the pandemic.

Antibodies to NCP, RBD and S2 SARS-CoV-2 in Vaccinated and Unvaccinated Healthcare Workers

In a few months, the SARS-CoV-2 virus caused a worldwide COVID-19 pandemic. In Poland, 6 million cases of the disease and 113,000 deaths from COVID-19 have been reported. Healthcare workers (HCWs) constitute one of the main COVID-19 risk groups. The Microblot-Array COVID-19 IgG assay was used to detect antibodies against three major SARS-CoV-2 antigens: nucleocapsid (NCP), RBD, and Spike 2 (S2). The aim of our study was to determine the seroprevalence and titer of anti-SARS-CoV-2 IgG antibodies—NCP, RBD, and S2—as markers of the humoral response in vaccinated and unvaccinated HCWs. The study included 203 persons who were divided into four groups: “COVID-19 Vaccinated”, “COVID-19 Unvaccinated”, “Non-COVID-19 Vaccinated”, and “Non-COVID-19 Unvaccinated”. The obtained results indicate that both seroprevalence and the antibody titer are the highest in the “COVID-19 Vaccinated” group. There is no so-called sterile vaccination, and after 6 months from the second dose of vaccine, most vaccinated people have a fairly high level of antibodies. We suggest that multiple vaccination and continuous testing are necessary. The Microblot-Array assay can distinguish between antibodies acquired after infection and/or vaccination.

SARS-CoV-2 Seroprevalence in Healthcare Workers before the Vaccination in Poland: Evolution from the First to the Second Pandemic Outbreak

Healthcare workers (HCWs) are on the frontline, struggling with the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To describe recent or past infections, the serological assays enabled the assessment of the immune response developed in coronavirus disease (COVID-19) in the period when testing was hardly available. In this study, we investigated SARS-CoV-2 seroprevalence in HCWs in a Polish teaching hospital and the Regional Occupational Medicine Center after both the first and the second waves. ELISA-based tests for anti-SARS-CoV-2 IgA and IgG were used to determine immune response to SARS-CoV-2 in volunteer HCWs who worked in those institutions in May 2020 (208 participants aged 47.1 ± 12.5, 88% women) and in December 2020 (179 participants aged 45.2 ± 12.4, 86% woman). Risk factors for seropositivity were also assessed using a questionnaire filled out by all participants. We reported a significant increase in seroprevalence after the second wave (22.9%) compared with the first outbreak (2.4%) (OR 12.1; 95%CI 4.6–31.3; p < 0.0001). An association between IgG seroprevalence and severity of infections was noted. Furthermore, we demonstrated that amongst medical personnel, nurses exhibited a proportionally higher SARS-CoV-2 seroprevalence. Moreover, given the high seroprevalence in non-clinical group of HCWs, we suggest that community transmission can play a superior role to workplace exposure.

The Complexity of SARS-CoV-2 Infection and the COVID-19 Pandemic

The pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to the death of millions of people worldwide and thousands more infected individuals developed sequelae due to the disease of the new coronavirus of 2019 (COVID-19). The development of several studies has contributed to the knowledge about the evolution of SARS-CoV2 infection and the disease to more severe forms. Despite this information being debated in the scientific literature, many mechanisms still need to be better understood in order to control the spread of the virus and treat clinical cases of COVID-19. In this article, we carried out an extensive literature review in order to bring together, in a single article, the biological, social, genetic, diagnostic, therapeutic, immunization, and even socioeconomic aspects that impact the SAR-CoV-2 pandemic. This information gathered in this article will enable a broad and consistent reading of the main aspects related to the current pandemic.

Seroprevalence of Anti-SARS-CoV-2 Antibodies in Benadir Region, Somalia

Only little is known about the true extent of COVID-19 in Somalia. The study aims to assess the seroprevalence of the COVID-19 pandemics in the Benadir region using SARS-CoV-2 antibodies and estimate the number of inhabitants infected with SARS-CoV-2. Population-based cross-sectional survey was conducted to measure the seroprevalence of antibodies against SARS-CoV-2 in the Benadir region (Mogadishu city). In the study, we enrolled 2500 Mogadishu city residents aged ≥18 years who did not receive the SARS-CoV-2 vaccine. The overall seroprevalence of IgG/IgM anti-SARS-CoV-2 antibodies was 44.8%. The seropositivity in females (56.6%) was higher than in males (46.2%). The trend in seropositivity increased with age; however, the variation was only significant in the age group 38–57 with an odds ratio and p-value of 4.11 (1.475–11.47), p = 0.007. Families with >5 members (47.2%) were more likely to test positive than those with <5 members (37%). Participants who reported COVID-19 symptoms during the pandemics or who had contact with COVID-19 patients had significantly increased IgG prevalence. Participants with larger families, individuals working in the public sector, and students showed significant seropositive results. Therefore, precautionary measures should be heightened for individuals working in the public sector.

SARS-CoV-2 Infection Prevalence in the Population of South-Eastern Poland

COVID-19 outbreak began in Wuhan, China, and has spread to other continents, including Europe, placing pressure on healthcare systems. Poland is one of the European countries with the highest number of SARS-CoV-2 infections and COVID-19-related deaths. The aim of this study was to analyze the presence of SARS-CoV-2 in the population of south-eastern Poland. The correlation between viral infection and demographic data (gender, age, place of residence) and cancer was also investigated. A total of 44,801 samples were tested, of which 4862 cases were diagnosed with SARS-CoV-2 infections. A total of 14,970 samples were tested in cancer patients. The RT-PCR method was used to detect viral nucleic acid. In this study, significantly, the highest rate of virus detection was among people living in Lublin and the lowest among people living in a small town (p < 0.0001). Moreover, there was no significant relationship between sex and the frequency of virus detection. The highest number of SARS-CoV-2 infections was observed in the age groups 10-19, 20-29, 30-39, and 90+ (p = 0.0001). In cancer patients, the percentage of positive cases was significantly lower than in the rest (p = 0.0001).

Impact of Two Different Recruitment Procedures (Random vs. Volunteer Selection) on the Results of Seroepidemiological Study (SARS-CoV-2)

The proper recruitment of subjects for population-based epidemiological studies is critical to the external validity of the studies and, above all, to the sound and correct interpretation of the findings. Since 2020, the novel coronavirus SARS-CoV-2 pandemic has been a new factor that has been, additionally, hindering studies. Therefore, the aim of our study is to compare demographic, socio-economic, health-related characteristics and the frequency of SARS-CoV-2 infection occurrence among the randomly selected group and the group composed of volunteers. We compare two groups of participants from the cross-sectional study assessing the seroprevalence of SARS-CoV-2 coronavirus, which was conducted in autumn 2020, in three cities of the Silesian Voivodeship in Poland. The first group consisted of a randomly selected, nationally representative, age-stratified sample of subjects (1167 participants, “RG” group) and was recruited using personal invitation letters and postal addresses obtained from a national registry. The second group (4321 volunteers, “VG” group) included those who expressed their willingness to participate in response to an advertisement published in the media. Compared with RG subjects, volunteers were more often females, younger and professionally active, more often had a history of contact with a COVID-19 patient, post-contact nasopharyngeal swab, fewer comorbidities, as well as declared the occurrence of symptoms that might suggest infection with SARS-CoV-2. Additionally, in the VG group the percentage of positive IgG results and tuberculosis vaccination were higher. The findings of the study confirm that surveys limited to volunteers are biased. The presence of the bias may seriously affect and distort inference and make the generalizability of the results more than questionable. Although effective control over selection bias in surveys, including volunteers, is virtually impossible, its impact on the survey results is impossible to predict. However, whenever possible, such surveys could include a small component of a random sample to assess the presence and potential effects of selection bias.

Retracted: The Safety of COVID-19 Vaccinations-We Should Rethink the Policy

Background: COVID-19 vaccines have had expedited reviews without sufficient safety data. We wanted to compare risks and benefits. Method: We calculated the number needed to vaccinate (NNTV) from a large Israeli field study to prevent one death. We accessed the Adverse Drug Reactions (ADR) database of the European Medicines Agency and of the Dutch National Register (lareb.nl) to extract the number of cases reporting severe side effects and the number of cases with fatal side effects. Result: The NNTV is between 200-700 to prevent one case of COVID-19 for the mRNA vaccine marketed by Pfizer, while the NNTV to prevent one death is between 9000 and 50,000 (95% confidence interval), with 16,000 as a point estimate. The number of cases experiencing adverse reactions has been reported to be 700 per 100,000 vaccinations. Currently, we see 16 serious side effects per 100,000 vaccinations, and the number of fatal side effects is at 4.11/100,000 vaccinations. For three deaths prevented by vaccination we have to accept two inflicted by vaccination. Conclusions: This lack of clear benefit should cause governments to rethink their vaccination policy.