Primary and Secondary Attack Rates by Vaccination Status after a SARS-CoV-2 B.1.617.2 (Delta) Variant Outbreak at a Youth Summer Camp-Texas, June 2021

J Pediatric Infect Dis Soc. 2022 Dec 28;11(12):550-556. doi: 10.1093/jpids/piac086.

Abstract

Children are capable of initiating COVID-19 transmission into households, but many questions remain about the impact of vaccination on transmission. Data from a COVID-19 Delta variant outbreak at an overnight camp in Texas during June 23-27, 2021, were analyzed. The camp had 451 attendees, including 364 youths aged < 18 years and 87 adults. Detailed interviews were conducted with 92 (20.4%) of consenting attendees and 117 household members of interviewed attendees with COVID-19. Among 450 attendees with known case status, the attack rate was 41%, including 42% among youths; attack rates were lower among vaccinated (13%) than among unvaccinated youths (48%). The secondary attack rate was 51% among 115 household contacts of 55 interviewed index patients. Secondary infections occurred in 67% of unvaccinated household members and 33% of fully or partially vaccinated household members. Analyses suggested that household member vaccination and camp attendee masking at home protected against household transmission.

Keywords: COVID-19; SARS-CoV-2; household transmission; vaccination; youth.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Child
  • Disease Outbreaks
  • Humans
  • Incidence
  • SARS-CoV-2*
  • Texas / epidemiology
  • Vaccination

Supplementary concepts

  • SARS-CoV-2 variants