Oon Tek Ng, Vanessa Koh, Calvin J Chiew, Kalisvar Marimuthu, Natascha May Thevasagayam, Tze Minn Mak, Joon Kiat Chua, Shannen Si Hui Ong, Yong Kai Lim, Zannatul Ferdous, Alifa Khairunnisa Bte Johari, Lin Cui, Raymond Tzer Pin Lin, Kelvin Bryan Tan, Alex R Cook, Yee Sin Leo, Vernon J M Lee
{"title":"Impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccination and Pediatric Age on Delta Variant Household Transmission.","authors":"Oon Tek Ng, Vanessa Koh, Calvin J Chiew, Kalisvar Marimuthu, Natascha May Thevasagayam, Tze Minn Mak, Joon Kiat Chua, Shannen Si Hui Ong, Yong Kai Lim, Zannatul Ferdous, Alifa Khairunnisa Bte Johari, Lin Cui, Raymond Tzer Pin Lin, Kelvin Bryan Tan, Alex R Cook, Yee Sin Leo, Vernon J M Lee","doi":"10.1093/cid/ciac219","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>In Singapore, quarantine of all close contacts with entry and exit polymerase chain reaction testing enabled evaluation of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and pediatric age on transmission of the Delta variant.</p><p><strong>Methods: </strong>This retrospective cohort study included all household close contacts between 1 March 2021 and 31 August 2021.</p><p><strong>Results: </strong>Among 8470 Delta variant-exposed contacts linked to 2583 indices, full-vaccination of the index with BNT162b2 or mRNA-1273 was associated with reduction in acquisition by contacts (adjusted odds ratio [aOR], 0.56; 95% robust confidence interval [RCI], .44-.71 and aOR, 0.51; 95% RCI, .27-.96, respectively). Compared with young adults (aged 18-29 years), children (aged 0-11 years) were significantly more likely to transmit (aOR, 2.37; 95% RCI, 1.57-3.60) and acquire (aOR, 1.43; 95% RCI, 1.07-1.93) infection, vaccination considered. Longer duration from vaccination completion among contacts was associated with decline in protection against acquisition (first-month aOR, 0.42; 95% RCI, .33-.55; fifth-month aOR, 0.84; 95% RCI, .55-.98; P < .0001 for trend) and symptomatic disease (first-month aOR, 0.30; 95% RCI, .23-.41; fifth-month aOR, 0.62; 95% RCI, .38-1.02; P < .0001 for trend). Contacts immunized with mRNA-1273 had significant reduction in acquisition (aOR, 0.73; 95% RCI, .58-.91) compared with BNT162b2.</p><p><strong>Conclusions: </strong>Among household close contacts, vaccination prevented onward SARS-CoV-2 transmission and there was in-creased risk of SARS-CoV-2 acquisition and transmission among children compared with young adults. Time after completion of vaccination and vaccine type affected SARS-CoV-2 acquisition.</p>","PeriodicalId":10421,"journal":{"name":"Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America","volume":" ","pages":"e35-e43"},"PeriodicalIF":0.0000,"publicationDate":"2022-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9129132/pdf/ciac219.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1093/cid/ciac219","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Background: In Singapore, quarantine of all close contacts with entry and exit polymerase chain reaction testing enabled evaluation of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and pediatric age on transmission of the Delta variant.
Methods: This retrospective cohort study included all household close contacts between 1 March 2021 and 31 August 2021.
Results: Among 8470 Delta variant-exposed contacts linked to 2583 indices, full-vaccination of the index with BNT162b2 or mRNA-1273 was associated with reduction in acquisition by contacts (adjusted odds ratio [aOR], 0.56; 95% robust confidence interval [RCI], .44-.71 and aOR, 0.51; 95% RCI, .27-.96, respectively). Compared with young adults (aged 18-29 years), children (aged 0-11 years) were significantly more likely to transmit (aOR, 2.37; 95% RCI, 1.57-3.60) and acquire (aOR, 1.43; 95% RCI, 1.07-1.93) infection, vaccination considered. Longer duration from vaccination completion among contacts was associated with decline in protection against acquisition (first-month aOR, 0.42; 95% RCI, .33-.55; fifth-month aOR, 0.84; 95% RCI, .55-.98; P < .0001 for trend) and symptomatic disease (first-month aOR, 0.30; 95% RCI, .23-.41; fifth-month aOR, 0.62; 95% RCI, .38-1.02; P < .0001 for trend). Contacts immunized with mRNA-1273 had significant reduction in acquisition (aOR, 0.73; 95% RCI, .58-.91) compared with BNT162b2.
Conclusions: Among household close contacts, vaccination prevented onward SARS-CoV-2 transmission and there was in-creased risk of SARS-CoV-2 acquisition and transmission among children compared with young adults. Time after completion of vaccination and vaccine type affected SARS-CoV-2 acquisition.