The safety and immunogenicity of a two-dose schedule of CoronaVac, and the immune persistence of vaccination for six months, in people living with HIV: A multicenter prospective cohort study.

Background: People living with HIV (PLWH) are more vulnerable to SARS-CoV-2. However, evidence on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in this population is insufficient. The objective of this study is to assess the immunogenicity and safety of the two-dose schedule of Sinovac CoronaVac for 6 months postvaccination in PLWH. Methods: We conducted a multicenter prospective cohort study among PLWH and HIV-negative adults in China. Participants who received two doses of CoronaVac prior to the recruitment were allocated into two groups and followed up for 6 months. The neutralizing antibodies (nAbs), immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG), and gamma-interferon (IFN-γ) were measured to assess the associations among CoronaVac immunogenicity and related factors. Adverse reactions were collected to evaluate the safety profile of vaccination. Results: A total of 203 PLWH and 100 HIV-negative individuals were enrolled. A small portion of participants reported mild or moderate adverse reactions without serious adverse events. Median nAbs level in PLWH (31.96 IU/mL, IQR: 12.34-76.40) was lower than that in the control group (46.52 IU/mL, IQR: 29.08-77.30) at the 2-4 weeks postvaccination (P=0.002), and the same trend was presented for median S-IgG titer (37.09 vs. 60.02 IU/ml) (both P <0.05). The nAbs seroconversion rate in the PLWH group was also lower than in the control group (75.86% vs. 89.00%). After then, the immune responses reduced over time in term of only 23.04% of PLWH and 36.00% of HIV-negative individuals had a positive seroconversion for nAbs at 6-month. The multivariable generalized estimating equation analysis showed that PLWH with CD4+T count≥350 cells/µL presented higher immune response than PLWH with CD4+T count <350 cells/µL in terms of antibody seroconversion and titers. The immunogenicity did not differ in participants with low or high HIV viral load. The S-antigen specific IFN-γ immunity was generally stable and had a slow attenuation in both two groups for 6 months postvaccination. Conclusion: The Sinovac CoronaVac was generally safe and immunogenic in PLWH, but the immunity response was inferior and the antibodies vanished faster compared to HIV-negative individuals. This study suggested a shorter than 6-month interval of prime-boost vaccination for PLWH to ensure a better protection.

Analysis of COVID-19 clustered outbreaks in Zhengzhou, China

The aim of this study was to understand epidemiological characteristics of aggravated epidemic situation of COVID-19 pneumonia in Zhengzhou and provide evidence for effective prevention and control measures., The data were collated and analyzed using epidemiological description methods. There was a total of 34 clustered outbreaks. Family (ethnic) group accounted for 85.29% (29/34), international travel group accounted for 5.88% (2/34), company group accounted for 2.94% (1/34), hospital group accounted for 5.88% (2/34). The number of clustered cases accounted for 61.15% (96/157) of the reported confirmed cases in Zhengzhou. 58.82% of the clustered outbreaks were related to other provinces and cities (including Wuhan). Among the clustered outbreaks, one of the follow-up cases occurred earlier than the indicated case, one occurred simultaneously with the indicated case. This study indicates that clustered epidemic of Zhengzhou is dominated by families, and it is necessary to implement centralized medical observation for all close contacts of cases. After resumption work and production, we should implement various related policies and be vigilant against the occurrence of cluster epidemics in enterprises and institutions. The subsequent cases occur earlier or at the same time as the indicated cases, suggesting that the incubation period is contagious.