Impact of risk for severe COVID-19 illness on physical activity during the pandemic

BACKGROUND

Precautions to mitigate spread of COVID-19 such as the closing of exercise facilities impacted physical activity behaviors. Varied risks for severe COVID-19 may have influenced participation in regular physical activity to maintain precautions.

OBJECTIVE

Describe differences in the amount and intensity of physical activity between adults at high versus low risk for severe COVID-19 illness during the pandemic. We hypothesized that over 13 months, 1) high-risk adults would have greater odds of inactivity than low-risk adults, and 2) when active, high-risk adults would have lower metabolic equivalent of task minutes (MET-min) than low-risk adults.

METHODS

This longitudinal observational cohort study surveyed U.S. adults' demographics, health history, and physical activity beginning March 2020 using REDCap. Using self-report, health history was assessed with a modified Charlson Comorbidity Index and physical activity with the International Physical Activity Questionnaire. Repeated physical activity measurements were conducted in June, July, October, and December of 2020, and in April of 2021. Two models, a logistic model evaluating physical inactivity (hypothesis 1) and a gamma model evaluating total MET-min for physically active individuals (hypothesis 2), were used. Models were controlled for age, gender, and race.

RESULTS

The final sample consisted of 640 participants (mean age 42.7 ± 15.7, 78% women, 90% white), with n = 175 categorized as high-risk and n = 465 as low-risk. The odds of inactivity for the high-risk adults were 2.8 to 4.1 times as high than for low-risk adults at baseline and 13 months. Active high-risk adults had lower MET-min levels than low-risk adults in March (28%, p = 0.001), June (29%, p = 0.002), and July of 2020 (30%, p = 0.005) only.

CONCLUSIONS

Adults at high risk of severe COVID-19 illness were disproportionately more likely to be physically inactive and exhibit lower MET-min levels than adults at low risk during the early months of the COVID-19 pandemic.

New chimeric splice junction in adenovirus type 2-simian virus 40 hybrid viral mRNA

We have examined hybrid viral RNAs synthesized in both human and monkey cells infected by three nondefective adenovirus type 2 (Ad2)-simian virus 40 (SV40) hybrid viruses; Ad2+ND1, Ad2+ND2, and Ad2+ND4. Most of the hybrid viral RNA molecules appeared to be initiated within adenoviral sequences, but were polyadenylated on their 3' end at the early SV40 mRNA polyadenylation site. The Ad2+ND4 stock of virus was not homogeneous, but consisted of two principle populations of viral DNA. Both populations contained a segment of SV40 DNA extending from the SV40 map positions 0.63 to 0.11 in a left-to-right orientation at adenovirus map position 0.82. One population contained an intact SV40 segment, whereas the other (representing 80 to 85% of the population) has a 500-base pair deletion mapping from approximately 0.60 to 0.50 SV40 map units. This deletion encompassed the SV40 DNA segment which encodes the early SV40 splice sites. Cells infected by the mixed Ad2+ND4 population induced the synthesis of at least three major SV40 RNA species among the hybrid viral transcripts. The most abundant of these hybrid mRNA's appeared only late in the lytic cycle, after the onset of viral DNA replication. It contained an RNA splice junction which extended from a donor (5') nucleotide within the adenoviral RNA sequences to an acceptor (3') splice site within the early region of SV40 at 0.46 SV40 map units. This SV40 acceptor splice site was remarkable in that its use has not been detected in the spliced viral mRNA's of SV40-infected or -transformed cells.