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.

IgG antibody response by ELISA using Wuhan and Lambda variant antigens in BBIBP-CORV vaccinated health care workers. / Anticuerpos IgG determinados mediante ELISA desarrollados con antígenos de linajes Wuhan y Lambda en trabajadores de salud vacunados con BBIBP-CORV.

OBJECTIVES: . To evaluate the IgG antibody response by ELISA using Wuhan and Lambda antigens in health care workers with and without history of SARS-CoV-2 infection prior to immunization with the first and second doses of Sinopharm vaccine (BBIBP-CorV). MATERIALS AND METHODS: . An analytical study was carried out in health care workers over 18 years of age. Fifty-one participants with history and 100 participants without history of SARS-CoV-2 infection, who received two doses of Sinopharm vaccine, were included. IgG antibodies were assessed 21 days after the first dose, 21 days after the second dose and 3 months after the second dose by in-house ELISA using the complete antigen of the Wuhan variant (B.1.1) and lambda variant (C-37) of SARS-CoV-2 virus. RESULTS: . Both groups showed a large increase in the percentage of people with antibodies after the second dose, however, this percentage decreased 3 months after the second dose. The difference between the antibody index measured by ELISA with Wuhan variant antigen versus the ELISA with lambda variant was significant (p<0.001). CONCLUSIONS: . There is a significant increase in the presence of IgG type antibodies after 15 days of the second dose of BBIBP-CorV vaccination in participants without previous infection and a decrease after 3 months of the second dose in the ratio of IgG antibody reactivity indexes in ELISAs with the variant antigen as with ELISAs with the lambda variant.

OBJETIVOS.: Evaluar la respuesta de anticuerpos IgG determinada mediante ELISA utilizando antígenos de los linajes Wuhan y Lambda en trabajadores de la salud con y sin antecedente de infección por SARS-CoV-2 previa a la inmunización con la primera y segunda dosis de la vacuna Sinopharm (BBIBP-CorV). MATERIALES Y MÉTODOS.: Se realizó un estudio analítico en trabajadores de salud mayores de 18 años. Se incluyeron 51 participantes con antecedente y 100 participantes sin antecedente de infección por SARS-CoV-2, quienes recibieron dos dosis de la vacuna Sinopharm. Los anticuerpos IgG se evaluaron 21 días después de la primera dosis, 21 días después de la segunda dosis y 3 meses después de la segunda dosis mediante una prueba de ELISA in house desarrollado utilizando el antígeno completo del linaje Wuhan (B) y del linaje Lambda(C.37) del virus de SARS-CoV-2. RESULTADOS.: En ambos grupos se observó un incremento del porcentaje de personas con anticuerpos luego de la segunda dosis, sin embargo, este porcentaje disminuyó luego de 3 meses de la segunda dosis. Se halló una diferencia significativa entre el índice de anticuerpos medido por ELISA con el antígeno del linaje Wuhan versus el ELISA con el linaje Lambda (p<0,001). CONCLUSIONES.: Existe un aumento significativo de la presencia de anticuerpos tipo IgG luego de 15 días de la segunda dosis de la vacunación con BBIP-CORV en los participantes sin infección previa y una disminución, luego de 3 meses de la segunda dosis, de la razón de índices de reactividad de anticuerpos IgG en los ELISA desarrollados con el antígeno de la variante como en los ELISA desarrollados con la variante Lambda.

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.

Evaluation of the humoral response induced by BBIBP-CorV vaccine by determining neutralizing antibodies in peruvian healthcare personnel. / Evaluación de la respuesta humoral inducida por la vacuna BBIBP-CorV mediante la determinación de anticuerpos neutralizantes en personal sanitario peruano.

OBJECTIVE.: To determine the titer of antibodies against the receptor binding domain (RBD) of the spike protein (S) in health personnel between the 4th and 12th week after receiving the BBIBP-CorV vaccine (Sinopharm). MATERIALS AND METHODS.: We included a total of 168 healthcare workers from two hospitals in the region, who complied with the complete Sinopharm vaccine schedule; serum antibodies were measured using the Elecsys® Anti-SARS-CoV-2 test. RESULTS.: All participants developed antibodies to the RBD domain. The lowest antibody titer level was 1.78 U/mL. Levels equal to or above 250 were found in 70 (41.7%) participants. The geometric mean was 82.6 (95% CI: 67.8-100.6). Women had higher antibody levels. Participants whose antibodies were measured between 4- and 7-weeks post-vaccination showed significantly higher antibody levels than patients whose antibody levels were measured between 10- and 12-weeks post-vaccination. Among patients with a history of COVID-19, antibody levels were found to be at or above 250 U/mL in 88% of cases, compared to 6% among those without a history of COVID-19, (p<0.001). CONCLUSION.: All participants immunized with BBIBPCorV vaccine were positive for antibodies against the SARS-CoV-2 spike protein RBD. The correlation between the titer level and protection against COVID-19, as well as the length of the protection provided by the vaccine, needs to be evaluated.

OBJETIVO.: Determinar el título de anticuerpos frente al dominio de unión al receptor (RBD) de la proteína espiga (S) en personal de salud entre la 4.ª y 12.ª semana luego de haber recibido la vacuna BBIBP-CorV (Sinopharm). MATERIALES Y MÉTODOS.: Se incluyeron 168 trabajadores de salud de dos hospitales de la región, quienes cumplían el esquema completo con vacuna de Sinopharm, y se realizó la medición de anticuerpos en suero mediante la prueba Elecsys® Anti-SARS-CoV-2. RESULTADOS.: Todos los participantes desarrollaron anticuerpos frente al dominio RBD. El valor mínimo fue de 1,78 U/mL. En 70 (41,7%) participantes se encontraron niveles iguales o por encima de 250. La media geométrica fue de 82,6 (IC 95% 67,8-100,6). Las mujeres presentaron un mayor nivel de anticuerpos. El grupo de participantes en los que se midieron anticuerpos entre las semanas 4 y 7 posvacunación mostró niveles de anticuerpos significativamente mayores que los pacientes cuyas determinaciones fueron realizadas entre las 10 y 12 semanas posvacunación. Entre los pacientes con antecedente de COVID-19, los niveles de anticuerpos se encontraron en cifras iguales o por encima de 250 U/mL en el 88% de casos, en comparación con 6% entre aquellos sin antecedente de COVID-19, (p<0,001). CONCLUSIÓN.: Todos los participantes inmunizados con la vacuna BBIBP-CorV presentaron positividad a anticuerpos frente al RBD de la proteína S del SARS-CoV-2. Es necesario evaluar la correlación entre la magnitud de los títulos y la protección frente a COVID-19 y el tiempo de protección conferido por la vacuna.