SARS-CoV-2 Seroprevalence in People Referred to Private Medical Laboratories in Different Districts of Tehran, Iran from May 2020 to April 2021

Evaluating the efficiency of ELISA, monoplex and multiplex probe-based real-time reverse-transcription PCR assays in the detection of SARS-CoV-2 (COVID-19) and influenza A and B viruses: A cross-sectional study

Background and Aims

The current study aimed to evaluate the efficiency of Enzyme-linked immunosorbent assay (ELISA) assay and monoplex and multiplex real-time reverse-transcription PCR (rRT-PCR) in the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A and B viruses (Flu A and Flu B).

Methods

The SARS-CoV-2 -specific IgG and IgM antibodies, as well as, Flu A (H1N1 and H3N2 serotypes) and Flu B virus antibodies were determined by ELISA assay. The one-step qRT-PCR method was used to detect the SARS-CoV-2 in nasopharyngeal swab samples. Furthermore, the presence of Flu A and B viruses was evaluated using probe-based RT-PCR. Simultaneous detection of SARS-CoV-2, Flu A and B viruses was performed by multiplex rRT-PCR assay.

Results

SARS CoV-2 IgM and IgG antibodies were detected in 33.3% and 58.3% of patients, respectively. In contrast, the SARS CoV-2 genome was detected in 50% of patients using the one-step monoplex RT-PCR assay. Flu A serotypes H1N1 and H3N2 were found in 16.7% and 8.3% of patients. Probe-based RT-PCR revealed that 39.3% of patients were positive for the Flu A virus. Multiplex rRT-PCR detect the SARS-CoV-2, Flu A, and Flu B in 50%, 39.3%, and 19% of samples, respectively. The sensitivity and specificity of multiplex rRT-PCR assay in comparison to monoplex RT-PCR were 100% and 55%, respectively. Coinfection with SARS-CoV-2, Flu A, and Flu B viruses was found in 9.5% of patients.

Conclusion

Multiplex rRT-PCR can be used as a repaid, cost-effective and suitable tool for molecular surveillance of SARS-CoV-2 and Flu A/B viruses.

Changing Patterns of SARS-CoV-2 Seroprevalence: A Snapshot among the General Population in Kuwait

We sought to assess pre-vaccination and post-vaccination seroprevalences of anti-SARS-CoV-2 antibodies in Kuwait and to compare antibody levels between vaccine types. In phase 1 (pre-vaccination period, n = 19,363), blood samples were collected before the launch of COVID-19 vaccination in Kuwait between 1 September and 31 December 2020. Blood samples for phase 2 (post-vaccination period, n = 4973) were collected between 1 September and 30 November 2021. We tested subjects for anti-SARS-CoV-2 antibodies using the DiaSorin LIAISON^® SARS-CoV-2 IgM and Trimeric S IgG tests. In the pre-vaccination period, the prevalence of SARS-CoV-2 IgM and IgG was 14.50% (95% CI: 14.01-15.00) and 24.89% (95% CI: 24.29-25.50), respectively. The trend of seropositivity increased with age and was higher for females and non-Kuwaiti participants (p < 0.0001). Interestingly, seroprevalence was significantly higher for those who had received one dose of BNT162b2 (95.21%) than those who had received one dose of ChAdOx1-nCov-19 (92.86%). In addition, those who reported receiving two doses had higher seroprevalence, 96.25%, 95.86%, and 94.93% for ChA-dOx1-nCov-19/AstraZeneca, mix-and-match, and BNT162b2 recipients, respectively. After the second dose, median spike-specific responses showed no significant difference between ChAdOx1-nCov-19 and BNT162b2. Furthermore, statistical analysis showed no significant difference between median anti-trimeric S antibody levels of vaccinated individuals according to sex, age, or nationality (p > 0.05). In contrast, a negative correlation between age and anti-trimeric S IgG titers of BNT162b2-vaccinated subjects was observed (r = -0.062, p = 0.0009). Antibody levels decreased with time after vaccination with both vaccines. Our findings indicate that seroprevalence was very low during the pre-vaccination period (25%) in the general population and was greater than 95% in the vaccinated population in Kuwait. Furthermore, ChAdOx1-nCov-19 and BNT162b2 are effective in generating a similar humoral response.

COVID-19 Vaccination Willingness and Acceptability in Multiple Sclerosis Patients: A Cross Sectional Study in Iran

Multiple sclerosis (MS) is a chronic, predominantly immune-mediated degenerative disease of the central nervous system. Due to prolonged use of immunomodulatory and immunosuppressive medications, vaccine hesitancy could be common among MS patients. Our main aim in the current study was to evaluate the willingness and acceptability of COVID-19 vaccination in patients with MS. In our multicenter cross-sectional questionnaire-based clinical study, 892 patients completed the questionnaire between May to June 2021. The questionnaire consisted of demographic data, MS disease-related factors, history of COVID-19 infection/vaccination, and any existing comorbidities. Statistical analysis was performed using SPSS software version 19. Overall, 68% of the participants expressed willingness to be vaccinated. Major causes of vaccine refusal in our patients were the fear of reducing the efficacy of disease modifying drugs (DMDs) upon vaccination as well as distrusting the vaccines and overestimation bias in the power of their innate immunity and potential COVID-19 resistance. Some demographic factors affected vaccination enthusiasm in our study. Our findings did not show significant correlation between the age and comorbidity and vaccine willingness. Only one-third of our patients received their vaccine information from healthcare providers. The majority of them received these data from official broadcasting channels and social media. However, despite several concerns, the willingness of COVD-19 vaccination in the Iranian MS patients is remarkable.