Details

Autor(en) / Beteiligte

• McCormick, David W.
• Konkle, Stacey L.
• Magleby, Reed
• Chakrabarti, Ayan K.
• Cherney, Blake
• Lindell, Kristine
• Namageyo-Funa, Apophia
• Visser, Susanna
• Soto, Raymond A.
• Donnelly, Marisa A.P.
• Stringer, Ginger
• Austin, Brett
• Beatty, Mark E.
• Stous, Sarah
• Albanese, Bernadette A.
• Chu, Victoria T.
• Chuey, Meagan
• Dietrich, Elizabeth A.
• Drobeniuc, Jan
• Folster, Jennifer M.
• Killerby, Marie E.
• Lehman, Jennifer A.
• McDonald, Eric C.
• Ruffin, Jasmine
• Schwartz, Noah G.
• Sheldon, Sarah W.
• Sleweon, Sadia
• Thornburg, Natalie J.
• Hughes, Laura J.
• Petway, Marla
• Tong, Suxiang
• Whaley, Melissa J.
• Kirking, Hannah L.
• Tate, Jacqueline E.
• Hsu, Christopher H.
• Matanock, Almea

Titel

SARS-CoV-2 infection risk among vaccinated and unvaccinated household members during the Alpha variant surge – Denver, Colorado, and San Diego, California, January–April 2021

Ist Teil von

• Vaccine, 2022-08, Vol.40 (33), p.4845-4855

Ort / Verlag

Netherlands: Elsevier Ltd

Erscheinungsjahr

2022

Quelle

MEDLINE

Beschreibungen/Notizen

• •Vaccination reduces the risk household transmission of SARS-CoV-2.•Fewer households with a fully vaccinated primary case had secondary cases.•The primary SARS-CoV-2 variant in this investigation was the Alpha variant.•Vaccinated secondary cases reported fewer symptoms than unvaccinated secondary cases. COVID-19 vaccination reduces SARS-CoV-2 infection and transmission. However, evidence is emerging on the degree of protection across variants and in high-transmission settings. To better understand the protection afforded by vaccination specifically in a high-transmission setting, we examined household transmission of SARS-CoV-2 during a period of high community incidence with predominant SARS-CoV-2 B.1.1.7 (Alpha) variant, among vaccinated and unvaccinated contacts. We conducted a household transmission investigation in San Diego County, California, and Denver, Colorado, during January-April 2021. Households were enrolled if they had at least one person with documented SARS-CoV-2 infection. We collected nasopharyngeal swabs, blood, demographic information, and vaccination history from all consenting household members. We compared infection risks (IRs), RT-PCR cycle threshold values, SARS-CoV-2 culture results, and antibody statuses among vaccinated and unvaccinated household contacts. We enrolled 493 individuals from 138 households. The SARS-CoV-2 variant was identified from 121/138 households (88%). The most common variants were Alpha (75/121, 62%) and Epsilon (19/121, 16%). There were no households with discordant lineages among household members. One fully vaccinated secondary case was symptomatic (13%); the other 5 were asymptomatic (87%). Among unvaccinated secondary cases, 105/108 (97%) were symptomatic. Among 127 households with a single primary case, the IR for household contacts was 45% (146/322; 95% Confidence Interval [CI] 40–51%). The observed IR was higher in unvaccinated (130/257, 49%, 95% CI 45–57%) than fully vaccinated contacts (6/26, 23%, 95% CI 11–42%). A lower proportion of households with a fully vaccinated primary case had secondary cases (1/5, 20%) than households with an unvaccinated primary case (66/108, 62%). Although SARS-CoV-2 infections in vaccinated household contacts were reported in this high transmission setting, full vaccination protected against SARS-CoV-2 infection. These findings further support the protective effect of COVID-19 vaccination and highlight the need for ongoing vaccination among eligible persons.