Effectiveness of the BBIBP-CorV vaccine in preventing infection and death in health care workers in Peru 2021

Background During 2021, Peru started the vaccination against SARS-CoV-2 using the BBIBP-CorV inactivated virus vaccine for health care workers (HCW). We aim to evaluate the effectiveness of the BBIBP-CorV vaccine to prevent SARS-CoV-2 infection and deaths among HCWs. Methods Retrospective cohort study, from February 9 to June 30, 2021, using national registries of health care workers, laboratory tests for SARS-CoV-2 and deaths. We calculated the vaccine effectiveness for preventing laboratory-confirmed SARS-CoV-2 infection, COVID-19-mortality, and all-cause mortality among partially immunized and fully immunized HCWs. An extension of Cox proportional hazards regression was used to model the mortality results, and Poisson regression was used to model SARS-CoV-2 infection. Results The study included 606,772 eligible HCWs, the mean age was 40 (IQR: 33.0, 51.0). In fully immunized HCW, the effectiveness for preventing all-cause mortality was 83.6 (95% CI: 80.2 to 86.4), 88.7 (95% CI: 85.1 to 91.4) for preventing COVID-19 mortality, and 40.3 (95% CI 38.9 to 41.6) for preventing SARS-CoV-2 infection. Conclusion The BBIBP-CorV vaccine showed high levels of effectiveness for preventing all-cause and COVID-19 deaths among fully immunized HCW. These results were consistent within different subgroups and sensitivity analyses. However, the effectiveness for preventing infection was suboptimal in this particular setting.

Effectiveness of the BBIBP-CorV vaccine in preventing infection and death in health care workers in Peru 2021.

BACKGROUND: During 2021, Peru started the vaccination against SARS-CoV-2 using the BBIBP-CorV inactivated virus vaccine for health care workers (HCW). We aim to evaluate the effectiveness of the BBIBP-CorV vaccine to prevent SARS-CoV-2 infection and deaths among HCWs. METHODS: Retrospective cohort study, from February 9 to June 30, 2021, using national registries of health care workers, laboratory tests for SARS-CoV-2 and deaths. We calculated the vaccine effectiveness for preventing laboratory-confirmed SARS-CoV-2 infection, COVID-19-mortality, and all-cause mortality among partially immunized and fully immunized HCWs. An extension of Cox proportional hazards regression was used to model the mortality results, and Poisson regression was used to model SARS-CoV-2 infection. RESULTS: The study included 606,772 eligible HCWs, the mean age was 40 (IQR: 33.0, 51.0). In fully immunized HCW, the effectiveness for preventing all-cause mortality was 83.6 (95% CI: 80.2 to 86.4), 88.7 (95% CI: 85.1 to 91.4) for preventing COVID-19 mortality, and 40.3 (95% CI 38.9 to 41.6) for preventing SARS-CoV-2 infection. CONCLUSION: The BBIBP-CorV vaccine showed high levels of effectiveness for preventing all-cause and COVID-19 deaths among fully immunized HCW. These results were consistent within different subgroups and sensitivity analyses. However, the effectiveness for preventing infection was suboptimal in this particular setting.

Relative vaccine effectiveness of the booster dose of COVID-19 vaccine for preventing death in individuals with a primary regimen based on the BBIBP-CorV, ChAdOx1-S, or BNT162b2 vaccines during the Omicron wave in Peru: A nested case-control study using national population data.

BACKGROUND: Studies have reported evidence about the effectiveness of a third dose with BNT162b2 for preventing hospitalization and death by COVID-19. However, there is little evidence regarding other primary vaccine schedules such as BBIBP-CorV and ChAdOx1-S. We estimated the relative vaccine effectiveness (RVE) of the booster dose versus the primary regimens of COVID-19 vaccines based on BBIBP-CorV, ChAdOx1-S, or BNT162b2 for preventing death during the Omicron wave in Peruvian adult people. METHODS: We carried out a nested case-control study with a risk set sampling of controls using data from Peru between December 20, 2021, and February 20, 2022 (during the Omicron wave). Data on vaccination, COVID-19 tests and deaths were collected from national surveillance databases. We performed conditional logistic regression models to estimate the RVE on the adult population. In addition, we executed sub-group analysis per age group (18 to 59 years, and 60 years or more) and per primary regime (based on BNT162b2, BBIBP-CorV, or ChAdOx1-S). RESULTS: Of the 11,188,332 people eligible to enter the study 1,974 met the case definition (death from COVID-19) and were matched to 9,183 controls. The overall RVE of a third dose to prevent death was 87.2% (84.2%-89.7%), which varied according to the primary regime (87.3% for BNT162b2, 82.0% for BBIPB-CorV-2, and 79.5% for ChAdOx-S). In older adults, the RVE was 87.1%, without significant variations according to the primary regime (86.1% for BNT162b2, 86.1 for BBIBP-CorV, and 82% for ChAdOx-S). CONCLUSIONS: The booster) dose of vaccine against COVID-19 had a high RVE for preventing death by COVID-19 in the Peruvian population in all primary regimes of vaccines during the Omicron wave. This effect was consistent in people over 60 years of age, the group most vulnerable to die from this infection.

Immunogenicity and reactogenicity of a third dose of BNT162b2 vaccine for COVID-19 after a primary regimen with BBIBP-CorV or BNT162b2 vaccines in Lima, Peru.

BACKGROUND: The administration of a third (booster) dose of COVID-19 vaccines in Peru initially employed the BNT162b2 (Pfizer) mRNA vaccine. The national vaccination program started with healthcare workers (HCW) who received BBIBP-CorV (Sinopharm) vaccine as primary regimen and elderly people previously immunized with BNT162b2. This study evaluated the reactogenicity and immunogenicity of the "booster" dose in these two groups in Lima, Peru. METHODS: We conducted a prospective cohort study, recruiting participants from November to December of 2021 in Lima, Peru. We evaluated immunogenicity and reactogenicity in HCW and elderly patients previously vaccinated with either two doses of BBIBP-CorV (heterologous regimen) or BTN162b2 (homologous regimen). Immunogenicity was measured by anti-SARS-CoV-2 IgG antibody levels immediately before boosting dose and 14 days later. IgG geometric means (GM) and medians were obtained, and modeled using ANCOVA and quantile regressions. RESULTS: The GM of IgG levels increased significantly after boosting: from 28.5±5.0 AU/mL up to 486.6±1.2 AU/mL (p<0.001) which corresponds to a 17-fold increase. The heterologous vaccine regimen produced higher GM of post-booster anti-SARS-CoV-2 IgG levels, eliciting a 13% increase in the geometric mean ratio (95%CI: 1.02-1.27) and a median difference of 92.3 AU/ml (95%CI: 24.9-159.7). Both vaccine regimens were safe and well tolerated. Previous COVID-19 infection was also associated with higher pre and post-booster IgG GM levels. CONCLUSION: Although both boosting regimens were highly immunogenic, two doses of BBIBP-CorV boosted with BTN162b2 produced a stronger IgG antibody response than the homologous BNT162b2 regimen in the Peruvian population. Additionally, both regimens were mildly reactogenic and well-tolerated.

Confirmed Severe Acute Respiratory Syndrome Coronavirus 2 Reinfections After a Second Wave With Predominance of Lambda in Lima and Callao, Peru.

Background: Coronavirus disease 2019 (COVID-19) infection is a major public health problem in the world and reinfections are becoming more frequent. Our main objective was to describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the capital of Lima and Callao, Peru. Methods: We searched in the Peruvian laboratory information system from April 2020 up to May 2021, looking for cases having 2 positive molecular tests for SARS-CoV-2 with more than 90 days between them. We performed genomic sequencing to the available pairs of samples and described the clinical characteristics, epidemiological impact, and genomic analysis of the confirmed reinfections. Results: There were 1 694 164 people with a positive diagnostic test for SARS-CoV-2 in Lima/Callao during the study period. Of these, 1695 had 2 positive molecular tests with more than 90 days between them. Two hundred eleven had both samples available for genomic analysis according to our selection criteria, and these were retrieved and submitted to sequencing. Thirty cases were confirmed to be SARS-CoV-2 reinfections with 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection and accounted for 19 (63.3%) of the 30 cases. Conclusions: We report 30 cases of confirmed SARS-CoV-2 reinfections. The Lambda variant was the most common cause of the second infections, in concordance with its predominant circulation during Peru's second wave. This report describes the largest series of confirmed reinfections by SARS-CoV-2 in Latin America.We describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 in Lima and Callao, durante la segunda ola en Peru. The Lambda variant (C.37) was the most common cause of the second infections.

How has COVID-19 impacted the civil registration and vital statistics system in Loreto, Perú? Evidence using process mapping and qualitative analysis.

OBJECTIVES: Accurate civil registration and vital statistics (CRVS) systems are the primary data source to measure the impact of the COVID-19 pandemic on mortality. This study assesses how the pandemic impacted CRVS system processes in Loreto region of Peru, one of the worst affected countries globally. DESIGN: Qualitative study. SETTING: Loreto, a remote region, which had the highest reported mortality rate in Peru during the pandemic. PARTICIPANTS: Semistructured individual interviews and documentary analysis were conducted between September 2020 and May 2021 with 28 key informants from eight institutions involved in death certification. Key informants were identified using a purposive sampling strategy commencing at the Health Directorate of Loreto, and the snowball method was used where a participant suggested another organisation or person. Information from key informants was used to compare business process maps of the CRVS system before and during the pandemic. RESULTS: During early May 2020, there were seven times more registered deaths than in earlier years, but key informants believed this underestimated mortality by 20%-30%. During the pandemic, families had to interact with more institutions during the death certification process. Several issues disrupted death certification processes, including the burden of increased deaths, the Environmental Health Directorate often removing a body without the family's express agreement, the creation of COVID-19 cemeteries where no death certificate was needed for burial, greater participation of funeral homes that often used outdated paper forms, and closure of civil registry offices. There was increased use of the online National Death System (SINADEF) but many users had problems with access. CONCLUSIONS: The pandemic substantially disrupted CRVS processes in Loreto, making death certification more difficult, placing greater burden on the family and leading to more participation from unregulated organisations such as funeral homes or cemeteries. These disruptions were impacted by limitations of the CRVS system's processes before the pandemic.