O-21 Secondary Clinical Attack Rate of COVID-19 and Associated Risk Factors in Jamaica using National Surveillance Data
Author(s):
K Webster-Kerr, A Grant, A Harris, J Wiggan, D Henningham, D Rowe, J Azille-Lewis, R Thorpe, T Mullings, C Lord, T Dawkins- Beharie, I Wellington, K Gordon-Johnson, N Martin-Chen, E Campbell, M Brown, T Roberts, J Duncan
Year of Presentation:
2023
Objective: To estimate the secondary clinical attack rate (SCAR) for COVID-19 and determine factors associated with SARS-CoV-2 transmission in Jamaica.
Methods: A cross-sectional analysis of surveillance data was conducted using confirmed COVID-19 cases reported to the National Surveillance Unit (NSU) from March 10 to July 31, 2020. Primary and secondary cases were identified through contact tracing. Definitions of confirmed, primary, and secondary cases were based on WHO guidelines, while close contacts were defined per the Ministry of Health and Wellness, Jamaica protocol. Frequency and proportions by age and sex were calculated. Poisson regression was used to compute SCAR and crude risk ratios were calculated.
Results: This analysis included 362 cases (30 primary, 332 secondary) and 1,337 contacts of primary cases. The overall SCAR was 12.6% (95% CI: 10.8-14.6), and the transportation setting had the highest transmission rate (43.8%, 95% CI: 20.9-91.8). Male primary cases had a 40% lower risk of infecting close contacts compared to females (RR 0.6, 95% CI: 0.4-0.9), while contacts in the 60-to-79-year age group were twice as likely to be symptomatic compared to those 20-to-39 years of age (RR 2.0, 95% CI: 1.1-3.8). Primary cases in the North East region had 70% lower risk of infecting close contacts (RR 0.3, 95% CI: 0.1-0.9) compared to those in the South East region.
Conclusion: Our study found differences in the SCAR by age, exposure setting and regional distribution. These data provide the basis for public health actions aimed at mitigating COVID-19 transmission.