Real-world Evaluation of the Effectiveness of Sinopharm COVID-19 Vaccine Against Symptomatic COVID-19 in an Omicron-Dominant Setting in Mozambique: A Test-Negative, Case-Control Study.
We evaluated the effectiveness of the Sinopharm coronavirus disease 2019 (COVID-19) vaccine, introduced in Mozambique, against the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), prevalent from March 2022 to December 2023.
A test-negative case-control study was nested in a community-based enhanced COVID-19 surveillance in seven healthcare facilities including mobile testing stations in the Dondo District, Mozambique, between March 2022 and December 2023. Participants were individuals aged ≥2 years with COVID-19-like symptoms for <10 days. Cases were those with polymerase chain reaction (PCR)-confirmed COVID-19. For each case, three PCR test-negative controls were matched, according to age (±5 years), sex, and date of PCR test (±7 days). Follow-up for all cases was conducted until disease resolution. Vaccine protection was assessed according to the association between complete vaccination and SARS-CoV-2 disease onset ≥14 days after vaccination.
The study did not reach the targeted sample size, and only a third were analyzed. A total of 253 cases were matched to 759 test-negative controls by age, sex, and testing date, a process known as matching. Among cases, 41% had one dose of Sinopharm, 53% had two doses, and 6% were unvaccinated. Among the test-negative controls, 37% had 1 dose, 57% had two doses, and 7% were unvaccinated. The adjusted vaccine effectiveness, calculated using matching and adjusted for age and PCR test date, was 18.0% (95% confidence interval, -85.3 to 63.7; P = .63). No COVID-19-positive participants required hospitalization.
In an Omicron-dominant setting, two doses of the Sinopharm vaccine did not show significant protection against symptomatic COVID-19. However, as our analysis was based on data from only a third of enrolled individuals with confirmed vaccination status, these findings should be interpreted with caution. Our results underscore the importance of real-time vaccine effectiveness evaluations to inform optimal rollout strategies in low- and middle-income countries.
A test-negative case-control study was nested in a community-based enhanced COVID-19 surveillance in seven healthcare facilities including mobile testing stations in the Dondo District, Mozambique, between March 2022 and December 2023. Participants were individuals aged ≥2 years with COVID-19-like symptoms for <10 days. Cases were those with polymerase chain reaction (PCR)-confirmed COVID-19. For each case, three PCR test-negative controls were matched, according to age (±5 years), sex, and date of PCR test (±7 days). Follow-up for all cases was conducted until disease resolution. Vaccine protection was assessed according to the association between complete vaccination and SARS-CoV-2 disease onset ≥14 days after vaccination.
The study did not reach the targeted sample size, and only a third were analyzed. A total of 253 cases were matched to 759 test-negative controls by age, sex, and testing date, a process known as matching. Among cases, 41% had one dose of Sinopharm, 53% had two doses, and 6% were unvaccinated. Among the test-negative controls, 37% had 1 dose, 57% had two doses, and 7% were unvaccinated. The adjusted vaccine effectiveness, calculated using matching and adjusted for age and PCR test date, was 18.0% (95% confidence interval, -85.3 to 63.7; P = .63). No COVID-19-positive participants required hospitalization.
In an Omicron-dominant setting, two doses of the Sinopharm vaccine did not show significant protection against symptomatic COVID-19. However, as our analysis was based on data from only a third of enrolled individuals with confirmed vaccination status, these findings should be interpreted with caution. Our results underscore the importance of real-time vaccine effectiveness evaluations to inform optimal rollout strategies in low- and middle-income countries.
Authors
Capitine Capitine, Aziz Aziz, Manhiça Manhiça, Tivane Tivane, Zumba Zumba, Nhumba Nhumba, Rebocho Rebocho, Miquicene Miquicene, Nguenha Nguenha, Langa Langa, Shrivastava Shrivastava, Yang Yang, Wang Wang, Park Park, Kyung Kyung, You You, Lee Lee, Park Park, Rakotozandrindrainy Rakotozandrindrainy, Kyoung Jo Kyoung Jo, Sherliker Sherliker, Sugimoto Sugimoto, Jeon Jeon, Binger Binger, Siribie Siribie, Kim Kim, Jani Jani, Marks Marks, Tadesse Tadesse
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