Anders B. Nygaard

Abstract There is a growing awareness of the importance of indoor microbiomes for human health. Given their complexity, these microbiomes can only be adequately surveyed using high throughput sequencing techniques. Oxford Nanopore’s MinION is the newest third generation sequencing technology on the market. With its many advantages such as portability, user friendliness, simplicity, speed of sequencing and long read length, the technology is now an actual contender to established sequencing platforms. MinION’s main disadvantage is a relatively low read accuracy compared to several other platforms, although this is constantly improving. The present study, which appears to be the first of its kind, provides the results of a preliminary analysis of the microbial communities in indoor environments based on 16S rRNA gene amplicon sequencing, using both the Oxford Nanopore Technologies (ONT) MinIOn and the Illumina MiSeq DNA sequencers. At the level of family and above, there was no significant difference between the microbial compositions as revealed by the two platforms. However, at the genus, and particularly at the species level, the ONT MinION reported greater taxonomic resolution than Illumina MiSeq.

In Norway, 91% of children aged 1–5 attend kindergarten where they are exposed to indoor microbiomes which can have relevance for development and health. In order to gain a better understanding of the composition of the indoor microbiome and how it is affected by occupancy over time, floor dust samples from a newly opened kindergarten were investigated. Samples were collected during an 11-month period. Samples were analyzed for bacterial composition using 16S rRNA gene sequencing. Samples were also screened for four clinically relevant antibiotic resistance genes. In addition, Petrifilm analyses were used to evaluate surface hygiene.

Objective To determine if daily supplementation with cod liver oil, a low dose vitamin D supplement, in winter, prevents SARS-CoV-2 infection, serious covid-19, or other acute respiratory infections in adults in Norway. Design Quadruple blinded, randomised placebo controlled trial. Setting Norway, 10 November 2020 to 2 June 2021. Participants 34 601 adults (aged 18-75 years), not taking daily vitamin D supplements. Intervention 5 mL/day of cod liver oil (10 µg of vitamin D, n=17 278) or placebo (n=17 323) for up to six months. Main outcome measures Four co-primary endpoints were predefined: the first was a positive SARS-CoV-2 test result determined by reverse transcriptase-quantitative polymerase chain reaction and the second was serious covid-19, defined as self-reported dyspnoea, admission to hospital, or death. Other acute respiratory infections were indicated by the third and fourth co-primary endpoints: a negative SARS-CoV-2 test result and self-reported symptoms. Side effects related to the supplementation were self-reported. The fallback method was used to handle multiple comparisons. Results Supplementation with cod liver oil was not associated with a reduced risk of any of the co-primary endpoints. Participants took the supplement (cod liver oil or placebo) for a median of 164 days, and 227 (1.31%) participants in the cod liver oil group and 228 (1.32%) participants in the placebo group had a positive SARS-CoV-2 test result (relative risk 1.00, multiple comparison adjusted confidence interval 0.82 to 1.22). Serious covid-19 was identified in 121 (0.70%) participants in the cod liver oil group and in 101 (0.58%) participants in the placebo group (1.20, 0.87 to 1.65). 8546 (49.46%) and 8565 (49.44%) participants in the cod liver oil and placebo groups, respectively, had ≥1 negative SARS-CoV-2 test results (1.00, 0.97 to 1.04). 3964 (22.94%) and 3834 (22.13%) participants in the cod liver oil and placebo groups, respectively, reported ≥1 acute respiratory infections (1.04, 0.97 to 1.11). Only low grade side effects were reported in the cod liver oil and placebo groups. Conclusion Supplementation with cod liver oil in the winter did not reduce the incidence of SARS-CoV-2 infection, serious covid-19, or other acute respiratory infections compared with placebo. Trial registration ClinicalTrials.gov NCT04609423.

Objective: We aimed to describe post-acute sequelae of SARS-CoV-2 infection (PASC) related symptoms 3-15 months after a positive test in SARS-CoV-2 unvaccinated and vaccinated participants with a breakthrough infection. Methods: Participants of the Norwegian COVID-19 cohort, without a positive SARS-CoV-2 test, completed a questionnaire about PASC-related symptoms between November 2020 and January 2021. About a year later, a second questionnaire (which also included the Everyday Memory Questionnaire [EMQ]-13) was completed by the same participants, most still without a positive SARS-CoV-2 test, but also by unvaccinated and vaccinated participants with a positive test 3-15 months before the questionnaire. Laboratory-confirmed SARS-CoV-2 status (positive or negative swab test determined by reverse transcriptase quantitative polymerase chain reaction) at the time of completing the questionnaire was ascertained from the Mandatory Norwegian Surveillance System for Communicable Diseases. Results: No differences were found in the self-reported PASC symptoms, dyspnea, fatigue, smell/taste changes, concentration problems, or the EMQ-13 score between unvaccinated and vaccinated participants 3-15 months after the positive test. Fewer memory problems were reported among vaccinated than unvaccinated participants. Conclusion: SARS-CoV-2 vaccines offer minor protection against PASC symptoms, although fewer memory problems were reported among the vaccinated than the unvaccinated participants.