key: cord-1035506-674l731a
authors: nan
title: Are low SARS-CoV-2 viral loads in infected children missed by RT-PCR testing?
date: 2021-05-27
journal: Lancet Reg Health Eur
DOI: 10.1016/j.lanepe.2021.100138
sha: 24828d909fba1ddae80b336be081c1cc285d42ac
doc_id: 1035506
cord_uid: 674l731a

nan

Are low SARS-CoV-2 viral loads in infected children missed by RT-PCR testing? [2] , which specifically discusses our findings of equally high attack rates in children and adults using serological assays. This commentary discusses SARS-CoV-2 transmission studies using RT-PCR from Iceland and a meta-analysis of attack rates [3, 4] .

Our study was performed at the start of the pandemic in Norway in an immunologically naïve population. Therefore, the family was the main, often only, source of infection in children. We found that nearly 90% of children had negative nasopharyngeal RT-PCR samples, yet they seroconverted 6 weeks later, confirming infection. The commentary proposes either poor sampling technique or late testing for the low RT-PCR positivity observed in children. However, the same sampling technique was used in children and adults, with a median time of testing 6 days after symptom debut, considered an optimal timing for RT-PCR testing. Transmission outside the household is unlikely, as schools and nurseries were closed. Community transmission was very low (3.9:100,000 infected) during this period. We believe that children simply had a lower viral load in the nasopharynx and therefore tested RT-PCR negative, but were infected and seroconverted at 6À8 weeks.

More recently, as the B.1.1.7 variant has become dominant in Norway, which is more transmissible with higher virus loads in the airways [5] , young children (<10) and 10À20 year olds are now among the most important groups testing positive in Norway, probably due to detectable virus in nasopharyngeal samples.

Nina Langeland, Rebecca Jane Cox on behalf of the Bergen COVID-19 Research Group

Should high household attack rates change public health polices? Lancet Region Health

Attack rates amongst household members of outpatients with confirmed COVID-19 in Bergen, Norway: a case-ascertained study

Household transmission of SARS-CoV-2: a systematic review and meta-analysis

Spread of SARS-CoV-2 in the icelandic population

Genomic characteristics and clinical effect of the emergent SARS-CoV-2 B1.1.7 lineage in London, UK: a whole-genome sequencing and hospital-based cohort study

Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

The Lancet Regional Health -Europe journal homepage: www.elsevier.com/lanepe