Research and analysis

COVID-19 Omicron variant: infectious period and asymptomatic and symptomatic transmission

These rapid reviews identify and summarise evidence about the infectious period of the COVID-19 Omicron variant, and transmission from people with asymptomatic or symptomatic infection.

• From: UK Health Security Agency
• Published: 12 April 2023
• Last updated: 9 January 2024 — See all updates

Documents

COVID-19 infectious period: A rapid evidence review (update 01)

Ref: GOV-15887. Published: 9 January 2024

PDF, 1.82 MB, 107 pages

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COVID-19 Omicron variant: infectious period and transmission from people with asymptomatic compared with symptomatic infection: a rapid review

Ref: GOV-14430. Published: 12 April 2023

PDF, 884 KB, 54 pages

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Incubation period, serial interval and infectious period for the Omicron variant of SARS-CoV-2: a rapid evidence briefing

Ref: GOV-15240. Originally available on request.

PDF, 292 KB, 15 pages

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Details

Three rapid reviews were conducted to identify and summarise evidence about the infectious period, serial interval and incubation period of the COVID-19 Omicron variant, and different transmission rates of people with asymptomatic or symptomatic infection.

COVID-19 infectious period: A rapid evidence review (update 01)

Published January 2024

This review is a partial update of the second review, only focusing on infectious period. It searched up to 4 September 2023 and included:

• 193 studies reporting on the infectious period of COVID-19:
  • 82 studies from the previous review
  • 111 studies from this updated review

COVID-19 Omicron variant: infectious period and transmission from people with asymptomatic compared with symptomatic infection: a rapid review

Published April 2023

This review searched up to 26 January 2023 and included:

• 82 studies reporting on the infectious period of the COVID-19 Omicron variant
• 10 studies reporting on the difference in transmission from people with asymptomatic compared with symptomatic COVID-19 infection

Incubation period, serial interval and infectious period for the Omicron variant of SARS-CoV-2: a rapid evidence briefing

Initially made available on request in 2022

This review searched up to 15 February 2022 for studies reporting on the incubation period, serial interval, and infectious period for the Omicron variant. It included 12 studies:

• 7 studies comparing Omicron and Delta variants
• 5 studies reporting on Omicron only

Published 12 April 2023
Last updated 9 January 2024 + show all updates

1. 9 January 2024

   Added 'COVID-19 infectious period: A rapid evidence review (update 01)'.

2. 18 September 2023

   Added 'Incubation period, serial interval and infectious period for the Omicron variant of SARS-CoV-2: a rapid evidence briefing'.

3. 12 April 2023

   First published.