tetano
Editor, Senior Moderator
Int J Epidemiol
. 2024 Aug 14;53(5):dyae116.
doi: 10.1093/ije/dyae116. Estimation of vaccine effectiveness against SARS-CoV-2-associated hospitalization using sentinel surveillance in South Africa
Nicola Chiwandire[SUP] 1 [/SUP], Sibongile Walaza[SUP] 1 2 [/SUP], Anne von Gottberg[SUP] 1 3 [/SUP], Nicole Wolter[SUP] 1 3 [/SUP], Mignon Du Plessis[SUP] 1 3 [/SUP], Fahima Moosa[SUP] 1 3 [/SUP], Michelle J Groome[SUP] 1 3 [/SUP], Jeremy Nel[SUP] 4 [/SUP], Ebrahim Variava[SUP] 4 5 [/SUP], Halima Dawood[SUP] 6 [/SUP], Mvuyo Makhasi[SUP] 1 2 [/SUP], Leora R Feldstein[SUP] 7 [/SUP], Perrine Marcenac[SUP] 8 [/SUP], Kathryn E Lafond[SUP] 8 [/SUP], Aaron M Samuels[SUP] 8 9 [/SUP], Cheryl Cohen[SUP] 1 2 [/SUP]
Affiliations
Background: COVID-19 vaccine effectiveness (VE) studies leveraging systematic surveillance in sub-Saharan Africa are limited. We assessed the effectiveness of two vaccines (Pfizer BNT162b2 and Johnson & Johnson Ad26.COV2.S) against SARS-CoV-2-associated hospitalization in South African adults aged ≥18 years.
Methods: We conducted a test-negative case-control study using pneumonia surveillance data in South Africa. Inpatients with physician-diagnosed lower respiratory tract infection or suspected COVID-19, testing SARS-CoV-2 positive or negative from June 2021-March 2022, were cases or controls, respectively. Fully vaccinated individuals received one Ad26.COV2.S dose or two BNT162b2 doses ≥14-days before enrollment. VE was estimated using multivariable logistic regression for Delta- and Omicron BA.1/BA.2-predominant periods, stratified by age and HIV status.
Results: The study included 925 cases and 1890 controls; 38 (4%) cases and 186 (10%) controls were fully vaccinated with BNT162b2, and 30 (3%) cases and 94 (5%) controls with Ad26.COV2.S. The vaccine effectiveness of BNT162b2 against SARS-CoV-2-associated hospitalization over Delta and Omicron BA.1/BA.2 periods was 91% (95% CI: 52%, 98%) and 33% (-16%, 86%), respectively. The vaccine effectiveness of Ad26.COV2.S against hospitalization over Delta and Omicron BA.1/BA.2 periods was 72% (-36% ,94%), and -19% (-130%, 39%), respectively. The vaccine effectiveness of BNT162b2 against hospitalization over the Delta period was 94% (50%, 99%) and 89% (27%, 98%) among adults aged ≥60 years and HIV-uninfected, respectively.
Conclusions: The BNT162b2 vaccine was effective against SARS-CoV-2-associated hospitalization during the Delta period for adults aged ≥18 years, ≥60 years and those HIV-uninfected. VE for Ad26.COV2.S was inconclusive, potentially due to limited sample size or residual confounding. These findings highlight the utility of sentinel surveillance for estimating VE.
Keywords: COVID-19; SARS-CoV-2; sentinel surveillance; test-negative case control; vaccine effectiveness.
. 2024 Aug 14;53(5):dyae116.
doi: 10.1093/ije/dyae116. Estimation of vaccine effectiveness against SARS-CoV-2-associated hospitalization using sentinel surveillance in South Africa
Nicola Chiwandire[SUP] 1 [/SUP], Sibongile Walaza[SUP] 1 2 [/SUP], Anne von Gottberg[SUP] 1 3 [/SUP], Nicole Wolter[SUP] 1 3 [/SUP], Mignon Du Plessis[SUP] 1 3 [/SUP], Fahima Moosa[SUP] 1 3 [/SUP], Michelle J Groome[SUP] 1 3 [/SUP], Jeremy Nel[SUP] 4 [/SUP], Ebrahim Variava[SUP] 4 5 [/SUP], Halima Dawood[SUP] 6 [/SUP], Mvuyo Makhasi[SUP] 1 2 [/SUP], Leora R Feldstein[SUP] 7 [/SUP], Perrine Marcenac[SUP] 8 [/SUP], Kathryn E Lafond[SUP] 8 [/SUP], Aaron M Samuels[SUP] 8 9 [/SUP], Cheryl Cohen[SUP] 1 2 [/SUP]
Affiliations
- PMID: 39305220
- PMCID: PMC11415825
- DOI: 10.1093/ije/dyae116
Background: COVID-19 vaccine effectiveness (VE) studies leveraging systematic surveillance in sub-Saharan Africa are limited. We assessed the effectiveness of two vaccines (Pfizer BNT162b2 and Johnson & Johnson Ad26.COV2.S) against SARS-CoV-2-associated hospitalization in South African adults aged ≥18 years.
Methods: We conducted a test-negative case-control study using pneumonia surveillance data in South Africa. Inpatients with physician-diagnosed lower respiratory tract infection or suspected COVID-19, testing SARS-CoV-2 positive or negative from June 2021-March 2022, were cases or controls, respectively. Fully vaccinated individuals received one Ad26.COV2.S dose or two BNT162b2 doses ≥14-days before enrollment. VE was estimated using multivariable logistic regression for Delta- and Omicron BA.1/BA.2-predominant periods, stratified by age and HIV status.
Results: The study included 925 cases and 1890 controls; 38 (4%) cases and 186 (10%) controls were fully vaccinated with BNT162b2, and 30 (3%) cases and 94 (5%) controls with Ad26.COV2.S. The vaccine effectiveness of BNT162b2 against SARS-CoV-2-associated hospitalization over Delta and Omicron BA.1/BA.2 periods was 91% (95% CI: 52%, 98%) and 33% (-16%, 86%), respectively. The vaccine effectiveness of Ad26.COV2.S against hospitalization over Delta and Omicron BA.1/BA.2 periods was 72% (-36% ,94%), and -19% (-130%, 39%), respectively. The vaccine effectiveness of BNT162b2 against hospitalization over the Delta period was 94% (50%, 99%) and 89% (27%, 98%) among adults aged ≥60 years and HIV-uninfected, respectively.
Conclusions: The BNT162b2 vaccine was effective against SARS-CoV-2-associated hospitalization during the Delta period for adults aged ≥18 years, ≥60 years and those HIV-uninfected. VE for Ad26.COV2.S was inconclusive, potentially due to limited sample size or residual confounding. These findings highlight the utility of sentinel surveillance for estimating VE.
Keywords: COVID-19; SARS-CoV-2; sentinel surveillance; test-negative case control; vaccine effectiveness.