Editorial
eMediNexus Coverage from:
Infectious period of the Omicron variant
Dr Veena Aggarwal, Consultant Womens’ Health, CMD and Editor-in-Chief, IJCP Group & Medtalks Trustee, Dr KK’s Heart Care Foundation of India, 11 January 2022
#Multispeciality
The infectious period of the Omicron variant is possibly 10 days, according to a preliminary study from Japan.1 The study carried out by the National Institute of Infectious Diseases (NIID) and the Disease Control and Prevention Center within the National Center for Global Health and Medicine (NCGM/DCC).
Researchers examined 83 respiratory samples collected from 21 cases. Out of these 19 were vaccinated and 2 were unvaccinated. Seventeen patients had mild infection, while 4 were asymptomatic. Quantitative reverse transcriptase polymerase chain reaction (RT qPCR) and virus isolation tests were done. Day 0 was considered as the day of collection of samples or onset of symptoms.
Analysis of samples revealed that the amount of viral RNA was highest between day 3 and day 6 after the onset of symptoms or diagnosis. The quantity of RNA was then seen to progressively decline. A marked decrease was seen after 10 days of diagnosis or symptom onset. A similar pattern was seen with positive virus isolation samples, where no infectious virus was detected after 10 days of diagnosis or symptom onset.
These are preliminary observations but they suggest that the maximum viral load is attained 3 to 6 days after the onset of symptoms and the infectious virus is shed up to 10 days after diagnosis or symptom onset.
Reference
- National Institute of Infectious Diseases Disease Control and Prevention Center, National Center for Global Health and Medicine. Active epidemiological investigation on SARS-CoV-2 infection caused by Omicron variant (Pango lineage B.1.1.529) in Japan: preliminary report on infectious period. January 5, 2022. https://www.niid.go.jp/niid/en/2019-ncov-e/10884-covid19-66-en.html
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