key: cord-0895886-3bd76ty7
authors: Pranay, Sinha; Reifler, Katherine; Rossi, Michael; Sagar, Manish
title: COVID-19 mitigation strategies were associated with decreases in other respiratory virus infections
date: 2021-03-20
journal: Open Forum Infect Dis
DOI: 10.1093/ofid/ofab105
sha: 4883cd94e700f8cd599ec3dc6eecf48c66974e44
doc_id: 895886
cord_uid: 3bd76ty7

Detection of diverse respiratory viruses in Boston was around 80% lower after practices were instituted to limit COVID-19 spread compared to the same time period during the previous five years. Continuing the strategies that lower COVID-19 dissemination may be useful in decreasing the incidence of other viral respiratory infections.

M a n u s c r i p t 3

After severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent for coronavirus disease 2019 (COVID-19), was declared a pandemic, physical distancing, mask-wearing, and other behavioral changes were adopted to limit virus transmission in the city of Boston [1] . Given that other common viral respiratory pathogens are also transmitted via aerosols, droplets, or contact, it is tenable that these measures may have reduced rates of infection by viruses other than SARS-CoV-2 [2] . In this brief report, we assess the impact of strategies aimed at decreasing SARS-CoV-2 spread on other respiratory viral infections.

Study design: We performed a retrospective cohort analysis to compare respiratory viral infections other than SARS CoV-2 in 2020 to corresponding periods in the previous five years.

Data collection: Similar to our previous investigation, we collected all documented respiratory virus infections on a comprehensive respiratory panel polymerase chain-reaction (CRP-PCR, BioFire Diagnostics) test at Boston Medical Center (BMC) from January 1, 2015

to November 25, 2020 [3] . The CRP-PCR detects nucleic acids for 20 common respiratory pathogens. We used a positive CRP-PCR test as a surrogate marker for viral infection. We excluded SARS-CoV-2 test results-positive or negative--because this analysis focused on the incidence of respiratory viruses commonly circulating prior to the COVID-19 pandemic.

We also obtained the patient age and level of medical care (inpatient, observation unit, emergency room, or outpatient) associated with each CRP-PCR test.

Descriptive statistics: COVID-19 mitigation practices started after March 10, 2020 (week 11) and data collection stopped on November 25, 2020 (week 47). Each year was divided into 2 periods: week 1week 10 (period 1) and week 12week 46 (period 2). Therefore, in 2020, period 1 corresponded to the phase prior to institution of A c c e p t e d M a n u s c r i p t 4 mitigation practices. Age groups (less than 18, 18 to 65, and greater than 65 years of age) and level of medical care (hospital-based or ambulatory) were compared using chi-square tests. Weekly viral testing data in the two 2020 periods was compared to the median for the corresponding weeks from the previous five years using matched pair Wilcoxon rank sum test. 

During period 1 (3,397 in 2020; range from 1,388 to 2,719 in 2015 -2019) and period 2 (6,976 in 2020; range from 2,285 to 4,977 in 2015 -2019), the number of CRP-PCR tests was higher in 2020 as compared to any of the previous 5 years (Table 1 ). The number of unique patients evaluated with a CRP-PCR was also higher in 2020 (period 1: 3,113; period 2: 5,939) as any of the 2015 to 2019 years (period 1: range 1,268 -2,469; period 2: range 2,010 -4,250). In 2020 period 2, pediatric patients (age < 18 years) were less frequently assessed with a CRP-PCR (p < 0.0001), and CRP-PCR tests were more frequently ordered while patients were at a hospital (inpatient, observation unit, or emergency department) rather than an ambulatory setting (p < 0.0001, Table 1 ). In contrast, CRP-PCR assessment was less frequent among older patients (age > 65 years, p = 0.009) A c c e p t e d M a n u s c r i p t 5 and those at a hospital (p < 0.0001) in 2020 period 1 as compared to the previous 5 years.

Thus, demographics and the care setting differed among the patients evaluated with a CRP-PCR test in 2020 period 2 compared to the previous five years.

In period 2, the cumulative number of detected viruses per week was significantly lower in 2020 (Table 1 and Supplementary Fig. 1) . Regardless of the suspected predominant route of transmission, decreases were observed for all the different respiratory viruses (influenza, parainfluenza viruses, metapneumoviruses, adenovirus, coronaviruses, enteroviruses, and respiratory syncytial virus) detected with a CRP-PCR test. The total number of viruses detected relative to the number of CRP-PCR tests was around 80% lower in 2020 period 2 compared to the previous 5 years (Supplementary Fig. 1B) .

Cumulative virus detection began to increase around week 30, which temporally coincides with the phased -re-opening‖ in Boston on July 20, 2020 ( Supplementary Fig. 1A) [1]. Similar to a previous investigation, there was a rise in rhinovirus infections about 2 to 3 weeks after the phased re-opening [4] . There was no difference in the cumulative number of Nonetheless, the cumulative number of detected viruses and the cumulative number of viruses relative to the number of CRP-PCR tests between week 30 to week 46 remained lower in 2020 as compared to previous five years ( Supplementary Fig. 1 ), although the difference was smaller compared to week 12 to week 29 ( Supplementary Fig. 2 ).

In multivariable logistic regression analysis, the odds of detecting a respiratory virus per test was significantly lower (aOR 0.16, 95% confidence interval [CI] 0.15 -0.18) in 2020 period 2 after adjusting for the level of medical care and patient age. The number of each pathogen detected, except for parainfluenza virus, was higher, in 2020 period 1 as compared to the period 1 for 2015 to 2019 (Table 1) . However, there was no difference in the proportion of CRP-PCR tests that were positive for viral pathogens in 2020 period 1 as A c c e p t e d M a n u s c r i p t 6 compared to the corresponding period in 2015 to 2019. The odds of detecting a respiratory virus per test in period 1 (aOR 1.06, 95%CI: 0.98 -1.14) was not different in 2020 as compared to 2015 to 2019 after adjusting for the level of medical care and patient age.

Previous studies have suggested that community level strategies employed to halt the spread of SARS-CoV-2 lowered influenza transmission [5] [6] [7] [8] . These previous This study has limitations. It is associative and does not prove causation.

Furthermore, our data is based on results available at BMC only, and they may not generalize to other settings. While a positive test on the CRP-PCR likely indicates active rather than a prior infection, detection of certain viruses may reflect asymptomatic carriage.

Additionally, differences in detection of individual viruses should be interpreted cautiously as this study may not have been powered to detect a difference. Our study also cannot determine which practice, such as mask wearing, physical distancing, school closures or others, was primarily associated with the observed decrease in cumulative virus detection.

Although this study design cannot establish causality, our findings are useful because they 

Transmission routes of respiratory viruses among humans

Recent endemic coronavirus infection is associated with less-severe COVID-19

Concomitant Marked Decline in Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Other Respiratory Viruses Among Symptomatic Patients Following Public Health Interventions in Australia: Data from St Vincent's Hospital and Associated Screening Clinics

Impact assessment of non-pharmaceutical interventions against coronavirus disease 2019 and influenza in Hong Kong: an observational study

Seasonal Influenza Activity During the SARS-CoV-2 Outbreak in Japan

Effects of COVID-19 Prevention Measures on Other Common Infections

Positive effects of COVID-19 control measures on influenza prevention

A c c e p t e d M a n u s c r i p t 7 suggest that continued vigilance in slowing SARS-CoV-2 spread may also ameliorate the impact from other respiratory pathogens, reducing the strain on healthcare infrastructure.Even once the pandemic resolves, practices implemented to reduce COVID-19 transmission may be advisable for vulnerable individuals such as the elderly or the immunocompromised, particularly in high-risk settings such as nursing homes, assisted living facilities, entertainment venues, or during travel, especially during the winter months at the annual peak of most respiratory viral infections. Furthermore, our analysis provides an estimate for the impact of the combined community and personal practices on viral infections, which is important for making public health decisions, developing mathematical models, and costeffectiveness analyses.A c c e p t e d M a n u s c r i p t 8

The authors report no potential conflicts.

This work was supported by grants from the NIH: K24 AI-145661 to MS and 5T32 AI-052074-13 to PS. The funding organization had no role in the design or conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. The work was facilitated by the Providence/Boston Center for AIDS Research (P30AI042853).

This work has not been presented at any meetings. c. Adjusted odds ratio calculated through binary logistic regression with age and level of care as covariates