tetano
Editor, Senior Moderator
Open Forum Infect Dis
. 2024 Feb 5;11(3)
fae065.
doi: 10.1093/ofid/ofae065. eCollection 2024 Mar. Overestimation of Severe Acute Respiratory Syndrome Coronavirus 2 Household Transmission in Settings of High Community Transmission: Insights From an Informal Settlement Community in Salvador, Brazil
Juan P Aguilar Ticona[SUP] 1 2 3 [/SUP], Nivison Nery Jr[SUP] 1 2 3 [/SUP], Matt Hitchings[SUP] 4 5 [/SUP], Emilia M M Andrade Belitardo[SUP] 2 [/SUP], Mariam O Fofana[SUP] 3 [/SUP], Murilo Dorión[SUP] 3 [/SUP], Renato Victoriano[SUP] 2 [/SUP], Jaqueline S Cruz[SUP] 2 [/SUP], Juliet Oliveira Santana[SUP] 2 [/SUP], Laise Eduarda Paixão de Moraes[SUP] 2 [/SUP], Cristiane W Cardoso[SUP] 2 6 [/SUP], Guilherme S Ribeiro[SUP] 2 7 [/SUP], Mitermayer G Reis[SUP] 2 3 7 [/SUP], Ricardo Khouri[SUP] 2 [/SUP], Federico Costa[SUP] 1 2 3 [/SUP], Albert I Ko[SUP] 2 3 [/SUP], Derek A T Cummings[SUP] 5 8 [/SUP]
Affiliations
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread globally. However, the contribution of community versus household transmission to the overall risk of infection remains unclear.
Methods: Between November 2021 and March 2022, we conducted an active case-finding study in an urban informal settlement with biweekly visits across 1174 households with 3364 residents. Individuals displaying coronavirus disease 2019 (COVID-19)-related symptoms were identified, interviewed along with household contacts, and defined as index and secondary cases based on reverse-transcription polymerase chain reaction (RT-PCR) and symptom onset.
Results: In 61 households, we detected a total of 94 RT-PCR-positive cases. Of 69 sequenced samples, 67 cases (97.1%) were attributed to the Omicron BA.1* variant. Among 35 of their households, the secondary attack rate was 50.0% (95% confidence interval [CI], 37.0%-63.0%). Women (relative risk [RR], 1.6 [95% CI, .9-2.7]), older individuals (median difference, 15 [95% CI, 2-21] years), and those reporting symptoms (RR, 1.73 [95% CI, 1.0-3.0]) had a significantly increased risk for SARS-CoV-2 secondary infection. Genomic analysis revealed substantial acquisition of viruses from the community even among households with other SARS-CoV-2 infections. After excluding community acquisition, we estimated a household secondary attack rate of 24.2% (95% CI, 11.9%-40.9%).
Conclusions: These findings underscore the ongoing risk of community acquisition of SARS-CoV-2 among households with current infections. The observed high attack rate necessitates swift booster vaccination, rapid testing availability, and therapeutic options to mitigate the severe outcomes of COVID-19.
Keywords: BA.1; Omicron; SARS-CoV-2; household transmission.
. 2024 Feb 5;11(3)
fae065.doi: 10.1093/ofid/ofae065. eCollection 2024 Mar. Overestimation of Severe Acute Respiratory Syndrome Coronavirus 2 Household Transmission in Settings of High Community Transmission: Insights From an Informal Settlement Community in Salvador, Brazil
Juan P Aguilar Ticona[SUP] 1 2 3 [/SUP], Nivison Nery Jr[SUP] 1 2 3 [/SUP], Matt Hitchings[SUP] 4 5 [/SUP], Emilia M M Andrade Belitardo[SUP] 2 [/SUP], Mariam O Fofana[SUP] 3 [/SUP], Murilo Dorión[SUP] 3 [/SUP], Renato Victoriano[SUP] 2 [/SUP], Jaqueline S Cruz[SUP] 2 [/SUP], Juliet Oliveira Santana[SUP] 2 [/SUP], Laise Eduarda Paixão de Moraes[SUP] 2 [/SUP], Cristiane W Cardoso[SUP] 2 6 [/SUP], Guilherme S Ribeiro[SUP] 2 7 [/SUP], Mitermayer G Reis[SUP] 2 3 7 [/SUP], Ricardo Khouri[SUP] 2 [/SUP], Federico Costa[SUP] 1 2 3 [/SUP], Albert I Ko[SUP] 2 3 [/SUP], Derek A T Cummings[SUP] 5 8 [/SUP]
Affiliations
- PMID: 38516384
- PMCID: PMC10957159
- DOI: 10.1093/ofid/ofae065
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread globally. However, the contribution of community versus household transmission to the overall risk of infection remains unclear.
Methods: Between November 2021 and March 2022, we conducted an active case-finding study in an urban informal settlement with biweekly visits across 1174 households with 3364 residents. Individuals displaying coronavirus disease 2019 (COVID-19)-related symptoms were identified, interviewed along with household contacts, and defined as index and secondary cases based on reverse-transcription polymerase chain reaction (RT-PCR) and symptom onset.
Results: In 61 households, we detected a total of 94 RT-PCR-positive cases. Of 69 sequenced samples, 67 cases (97.1%) were attributed to the Omicron BA.1* variant. Among 35 of their households, the secondary attack rate was 50.0% (95% confidence interval [CI], 37.0%-63.0%). Women (relative risk [RR], 1.6 [95% CI, .9-2.7]), older individuals (median difference, 15 [95% CI, 2-21] years), and those reporting symptoms (RR, 1.73 [95% CI, 1.0-3.0]) had a significantly increased risk for SARS-CoV-2 secondary infection. Genomic analysis revealed substantial acquisition of viruses from the community even among households with other SARS-CoV-2 infections. After excluding community acquisition, we estimated a household secondary attack rate of 24.2% (95% CI, 11.9%-40.9%).
Conclusions: These findings underscore the ongoing risk of community acquisition of SARS-CoV-2 among households with current infections. The observed high attack rate necessitates swift booster vaccination, rapid testing availability, and therapeutic options to mitigate the severe outcomes of COVID-19.
Keywords: BA.1; Omicron; SARS-CoV-2; household transmission.