ABSTRACT
What is already known about this topic?: Healthcare workers (HCWs) and previously infected patients (PIPs) may experience a wave of epidemic following the modification of the country's coronavirus disease (COVID)-zero policy in China. What is added by this report?: As of early January 2023, the initial wave of the COVID-19 pandemic among HCWs had effectively subsided, with no statistically significant differences observed in infection rates compared to those of their co-occupants. The proportion of reinfections among PIPs was relatively low, particularly in those with recent infections. What are the implications for public health practice?: Medical and health services have resumed normal operations. For patients who have recently experienced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, appropriate relaxation of policies may be considered.
ABSTRACT
Background: To investigate the anti-spike antibody response to vaccination in kidney transplant recipients (KTRs) previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as compared with KTRs with no history of coronavirus disease 2019 (COVID-19) from India. Methods: SARS-CoV-2 spike immunoglobulin (Ig) G antibody response was measured in 105 post-COVID-19 KTRs with PCR-confirmed SARS-CoV-2 infection who received either no vaccination (cohort 1), a single dose (cohort 2) or two doses (cohort 3) of vaccine and compared with 103 two-dose vaccinated COVID-19-naïve KTRs with no history of COVID-19 (cohort 4). Results: Out of 103 COVID-19-naïve two-dose vaccinated KTRs, <50% became seropositive with anti-spike antibody titres >50 arbitrary unit/mL subsequent to complete vaccination, the seroconversion rate being comparable in subjects receiving CovishieldTM versus CovaxinTM vaccines. However, the seropositive KTRs vaccinated with CovishieldTM had higher anti-spike antibody titres as compared with those who received CovaxinTM. We observed higher anti-SARS-CoV-2 spike antibody levels in post-COVID-19 KTRs after one dose of vaccine as compared with COVID-19-naïve two-dose vaccinated KTRs. Importantly, the second dose in post-COVID-19 KTRs did not significantly increase anti-spike antibody levels compared with the single-dose recipients. Conclusions: Our data present that in KTRs with previous SARS-CoV-2 infection, a single dose of vaccine (CovishieldTM) may be effective in mounting an optimal immune response. In contrast, COVID-19-naïve two-dose vaccinated KTRs respond poorly (<50%) to the current recommendation of a two-dose regimen in India.
ABSTRACT
We aimed to investigate neutralizing antibody titers (NtAbT) to the P.1 and B.1 SARS-CoV-2 variants in a cohort of healthy health care workers (HCW), including 20 previously infected individuals tested at baseline (BLinf, after a median of 298 days from diagnosis) and 21 days after receiving one vaccine dose (D1inf) and 15 uninfected subjects tested 21 days after the second-dose vaccination (D2uninf). All the subjects received BNT162b2 vaccination. D1inf NtAbT increased significantly with respect to BLinf against both B.1 and P.1 variants, with a fold-change significantly higher for P.1. D1inf NtAbT were significantly higher than D2uninf NtAbT, against B.1 and P.1. NtAbT against the two strains were highly correlated. P.1 NtAbT were significantly higher than B.1 NtAbT. This difference was significant for post-vaccination sera in infected and uninfected subjects. A single-dose BNT162b2 vaccination substantially boosted the NtAb response to both variants in the previously infected subjects. NtAb titers to B.1 and P.1 lineages were highly correlated, suggesting substantial cross-neutralization. Higher titers to the P.1 than to the B.1 strain were driven by the post-vaccination titers, highlighting that cross-neutralization can be enhanced by vaccination.