Last data update: May 28, 2024. (Total: 46864 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Konkle SL [original query] |
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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.
McCormick DW , Konkle SL , Magleby R , Chakrabarti AK , Cherney B , Lindell K , Namageyo-Funa A , Visser S , Soto RA , Donnelly MAP , Stringer G , Austin B , Beatty ME , Stous S , Albanese BA , Chu VT , Chuey M , Dietrich EA , Drobeniuc J , Folster JM , Killerby ME , Lehman JA , McDonald EC , Ruffin J , Schwartz NG , Sheldon SW , Sleweon S , Thornburg NJ , Hughes LJ , Petway M , Tong S , Whaley MJ , Kirking HL , Tate JE , Hsu CH , Matanock A . Vaccine 2022 40 (33) 4845-4855 BACKGROUND: 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. METHODS: 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. RESULTS: 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%). CONCLUSIONS: 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. |
Household transmission of SARS-CoV-2 Alpha variant - United States, 2021.
Donnelly MAP , Chuey MR , Soto R , Schwartz NG , Chu VT , Konkle SL , Sleweon S , Ruffin J , Haberling DL , Guagliardo SAJ , Stoddard RA , Anderson RD , Morgan CN , Rossetti R , McCormick DW , Magleby R , Sheldon SW , Dietrich EA , Uehara A , Retchless AC , Tong S , Folster JM , Drobeniuc J , Petway ME , Austin B , Stous S , McDonald E , Jain S , Hudziec MM , Stringer G , Albanese BA , Totten SE , Staples JE , Killerby ME , Hughes L , Matanock A , Beatty M , Tate JE , Kirking HL , Hsu CH . Clin Infect Dis 2022 75 (1) e122-e132 BACKGROUND: In Spring 2021, SARS-CoV-2 B.1.1.7 (Alpha) became the predominant variant in the U.S. Research suggests that Alpha has increased transmissibility compared to non-Alpha lineages. We estimated household secondary infection risk (SIR), assessed characteristics associated with transmission, and compared symptoms of persons with Alpha and non-Alpha infections. METHODS: We followed households with SARS-CoV-2 infection for two weeks in San Diego County and metropolitan Denver, January to April 2021. We collected epidemiologic information and biospecimens for serology, RT-PCR, and whole genome sequencing. We stratified SIR and symptoms by lineage, and identified characteristics associated with transmission using Generalized Estimating Equations. RESULTS: We investigated 127 households with 322 household contacts; 72 households (56.7%) had member(s) with secondary infections. SIRs were not significantly higher for Alpha (61.0% [95% confidence interval (CI) 52.4-69.0%]) than non-Alpha (55.6% [CI 44.7-65.9%], P = 0.49). In households with Alpha, persons who identified as Asian or Hispanic/Latino had significantly higher SIRs than those who identified as White (P = 0.01 and 0.03, respectively). Close contact (e.g., kissing, hugging) with primary cases was associated with increased transmission for all lineages. Persons with Alpha infection were more likely to report constitutional symptoms than persons with non-Alpha (86.9% vs. 76.8%, P = 0.05). CONCLUSIONS: Household SIRs were similar for Alpha and non-Alpha. Comparable SIRs may be due to saturation of transmission risk in households owing to extensive close contact, or true lack of difference in transmission rates. Avoiding close contact within households may reduce SARS-CoV-2 transmission for all lineages among household members. |
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- Page last updated:May 28, 2024
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