ABSTRACT
Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have played a crucial role in mitigating the coronavirus disease 2019 (COVID-19) pandemic. However, few studies have addressed the optimal booster vaccine type in recipients of the primary series of BBIBP-CorV (an inactivated virus vaccine developed by Sinopharm). This study aimed to estimate the association between the heterologous or homologous COVID-19 vaccination and SARS-CoV-2 infection. The study enrolled healthcare personnel (HCP) who had completed two doses of BBIBP-CorV between November 2020 and September 2021. The associations between SARS-CoV-2 infection and boosters were measured using multivariable logistic regression, comparing the odds of a positive COVID-19 test result between the no booster group and booster groups (BNT162b2 {Pfizer-BioNTech COVID-19 vaccine} group and BBIBP-CorV group, respectively). A total of 495 HCP comprising 326 (65.9%) in the BNT162b2 group, 121 (24.4%) in the no booster group, and 48 (9.7%) in the BBIBP-CorV group enrolled. One hundred thirty-six cases (27.5%) tested positive for COVID-19. The odds ratios for testing positive after booster dose were 0.401 (95% CI: 0.187-0.860, p = 0.019) and 0.446 (95% CI: 0.170-1.167, p = 0.100) for BNT162b2 and BBIBP-CorV group, respectively. The BNT162b2 booster in HCP after a second dose of BBIBP-CorV, relative to no booster, and the BBIBP-CorV booster, was associated with protection against laboratory-confirmed COVID-19.
ABSTRACT
Introduction: False-positive inconclusive polymerase chain reaction (PCR) results against severe acute respiratory syndrome coronavirus 2 were not low and have potentially harmful effects. We aimed to find parameters to differentiate positive cases from false-positive ones, and suggest an optimal scheme and follow-up period for inconclusive results. Methods: Cases with inconclusive PCR tests among healthcare personnel from February 2020 to June 2021 were classified as confirmed positive, clinically positive, and clinically negative groups, which were compared. The diagnostic accuracy of follow-up tests and composites of clinical and laboratory data were analyzed. Results: Symptoms, contact history, and lower cycle threshold of the N gene were more common in the COVID-19 positive group. The scoring schemes combining symptom and contact history with follow-up PCR results had higher sensitivities than the PCR tests only modality. Follow-up tests up to 5 days combined with symptoms and contact history could discriminate between positive and negative cases. Conclusion: A follow-up PCR test up to day 5 with clinical features might predict positivity and shorten the quarantine period in most healthcare personnel.