key: cord-0992251-e83cxuyc
authors: Tan, J.Y.; Conceicao, E.P.; Sim, X.Y.J.; Wee, L.E.I.; Aung, M.K.; Venkatachalam, I.
title: Public health measures during COVID-19 pandemic reduced hospital admissions for community respiratory viral infections
date: 2020-07-28
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2020.07.023
sha: 9d77909c161466c0154122f2edf7de824d5af31d
doc_id: 992251
cord_uid: e83cxuyc

nan

Sir, During the COVID-19 pandemic, Singapore implemented various measures to mitigate the transmission of COVID-19. These included border controls, social distancing, community education, a lockdown and compulsory wearing of masks in public. We report that public health measures were not only able to reducing COVID-19 transmission but also reduced transmission of endemic community respiratory viral infections.

We compared the number of hospital admissions for respiratory viral infections since the beginning of the Covid-19 outbreak, with the preceding 3 years at Singapore General Hospital. We looked at all laboratory confirmed community onset (defined as a positive respiratory viral swab within 72 hours of admission) respiratory viruses that were admitted to our hospital from 1 st January 2017 to 1 st July 2020. Patients with respiratory viral infections were confirmed using a 16-target respiratory viral PCR assay (Respiratory syncytial virus A/B, Influenza A/B, Parainfluenza viruses 1-4, Metapneumovirus, Rhinovirus A/B/C, Human Coronavirus OC43/229E/NL63, Adenovirus, Human Enterovirus, Human Bocavirus 1-4) on oropharyngeal specimens.

We observed a significant decrease in hospital admissions for both non-influenza respiratory viruses and influenza (Figure 1a and 1b) from EW 7 onwards. We compared epidemiological weekly (EW) positive rates (positive swabs divided by total number of swabs Consequently, the number of intensive care unit (ICU) admissions for respiratory viruses also decreased.

The implementation of public health measures to curb COVID-19 transmission had an unintended but beneficial consequence of reducing respiratory viral infection hospital admissions. Two other studies in Singapore had reported reduction in influenza cases as a consequence of COVID-19 public health measures (1, 2) . Both studies however ended before the influenza season. Our study reported lowest rates in past 3 years even during the influenza season, strongly supporting the effectiveness of public health measures. This is consistent with national data which also reported lowest ever influenza incidence in the community from EW 14 to EW 23 (3).

We depicted the chronological implementation of public health measures to match these measures with the decrease in weekly respiratory virus hospital admissions and hopefully evaluate their individual effectiveness. The Global Influenza Programme had reported the effectiveness of various non-pharmaceutical measures to prevent influenza transmission (4) . In Singapore, the combination of public health measures effectively reduced community respiratory virus admissions. Unfortunately, it is difficult to accurately assess the effectiveness of each individual public health measure. Each sequential measure additively contributed to the reduction in respiratory viral admissions to our hospital. Our findings suggest that measures such as social distancing and public hygiene are indeed effective in reducing respiratory viral transmission, as demonstrated by the drop in cases after EW 7. The lockdown helped to further halt transmission and reduce hospital admissions, though a measure not feasible in the long run. The compulsory wearing of masks was implemented during the lockdown period (EW15 onwards), and makes it difficult to assess how effective this measure by itself is, in reducing transmission rates. However, when Singapore entered phase 2 of reopening on 19 th June (EW25) and allowed social gatherings limited to 5 people while continuing to emphasize compulsory wearing of masks in public, the number of admissions continued to remain low. As Singapore continues to re-open, allowing bigger social gatherings, future studies will potentially be able to evaluate the true effectiveness of wearing face-masks as this measure is likely to continue.

Respiratory viruses will continue to circulate in the community and cause significant morbidity to atrisk populations (5) . Social distancing while effective may not be sustainable as a long-term measure. Face-mask on the other hand, though unsure in effectiveness, is a simple and practical measure and can potentially help reduce transmission rates. This has potential impact on current and future public health recommendations, especially for vulnerable groups of populations such as the elderly, patients with chronic lung diseases and the immunocompromised that can have severe consequences from a run-off-the-mill respiratory viral infection. 

Unintended Consequence: Influenza plunges with public health response to COVID-19 in Singapore

Ministry of Health Singapore CDD

Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza. Global Influenza Programme

Impact of Respiratory Virus Infections on Persons With Chronic Underlying Conditions