Respiratory Illness Dashboard

The Respiratory Illness Data Dashboard presents COVID-19, influenza and RSV surveillance data for Spokane County. This dashboard serves to:

1. Promote awareness of respiratory illness activity Spokane County
2. Mark the onset of respiratory illness season
3. Assist the healthcare provider community in infection control policy decision making

An overview of the dashboard and interpretation guidance is outlined here. The dashboard is updated weekly.

Overview

Weekly percentages of emergency department (ED) visits with a COVID-19, influenza or RSV diagnosis are posted on the Season Overview tab, along with the epidemic threshold for each disease. View the percent ED activity for any season by hovering over any point in the line chart. The dashboard also includes separate tabs for hospitalizations, mortality and long-term care outbreaks, and wastewater surveillance data.

Determination of Elevated Respiratory Illness Activity and Response

Elevated respiratory illness activity warrants the consideration of additional infection prevention measures in the healthcare community. This occurs when one or more of the following thresholds are met:

• At least one pathogen (COVID-19, influenza or RSV) reaches or exceeds the epidemic threshold (epidemic level) for emergency department visits (ED discharge diagnoses) in the Spokane Respiratory Illness Data Dashboard. Epidemic levels of percentage of weekly ER visits for COVID-19, influenza and RSV in Spokane County are 3.4 % for COVID-19, 0.9% for influenza, and 0.3% for RSV. Threshold levels can be viewed in the dashboard’s Weekly Emergency Department Visits section.

When one of the above thresholds is met, SRHD encourages healthcare facilities and providers to strongly consider universal masking in patient care areas, at the discretion of the individual healthcare facility’s respiratory illness infection control policy. As an example, many health care providers in Washington state keep universal masking in effect until:

• ED visits for all three pathogens are below their respective epidemic thresholds

Background

Spokane Regional Health District (SRHD) partnered with Washington State Department of Health (DOH), City of Spokane Riverside Park Water Reclamation Facility, and Spokane County Regional Water Reclamation Facility (SCRWRF) to establish a respiratory illness wastewater monitoring system in Spokane County.

Overview

The wastewater surveillance portion of the Respiratory Illness Dashboard provides information on the quantity of SARS-CoV-2, RSV and influenza virus detected in wastewater facilities in Spokane County. Samples collected from these facilities are tested for the presence of viral N genes, which are relatively stable as viruses evolve. The results are then normalized to represent the number of gene copies per day per person served by the facility, using calculations based on virus particles detected, wastewater flow rate, and population size.

This sampling method offers advantages over individual diagnostic testing. The data collected is shared with the Centers for Disease Control and Prevention (CDC) to contribute to their wastewater surveillance data, aiding in assessing public health measures and national trends.

Why is Wastewater Monitoring Important?

Wastewater monitoring is a valuable tool for public health and community leaders, enabling them to simultaneously monitor entire communities and gain crucial situational awareness regarding respiratory illness trends in Spokane County. This approach complements the epidemiological data derived from individual diagnostic testing.

By employing wastewater monitoring, changes in community viral load can be detected before they become apparent in diagnostic test results. This is primarily due to logistical factors associated with individuals seeking testing, awaiting results, or delayed reporting. Wastewater monitoring, in conjunction with state-reported testing trends, allows public health authorities to better serve and inform the community.

Report Positive At-Home Tests

Learn about how to quickly report positive at-home test results.

More Information

CDC National Wastewater Surveillance System (NWSS)

Threshold Calculation

Epidemic thresholds: Epidemic thresholds were derived from historical Spokane County emergency department disease data using the Moving Epidemic Method (MEM), which is designed to detect seasonal and temporal patterns in disease incidence.

Emergency department (ED) visits with diagnostic codes for respiratory illness for flu seasons 2017-2018, 2018-2019, 2019-2020, 2022-2023, and 2023-2024 were used for the calculations. Data for the 2021-2022 season were excluded because of atypically high COVID-19 transmission. RSV and influenza data from 2020-2021 were excluded due to atypically low influenza and RSV transmission. The unusually low incidence of flu and RSV during this season was likely influenced by universal masking and other community-wide disease control measures. Multiple waves of COVID-19 were accounted for by using the Moving Epidemic Method Web Application.

For the purposes of this dashboard and threshold calculations, respiratory illness season begins at week 40, typically the first week of October, and continues until week 39 of the following year.

Over epidemic threshold: Transmission of this illness is greater than what is typically observed throughout the year.

Below epidemic threshold: Transmission of this illness is less than or typical of what is observed throughout the year.

Trend Classification

The trend communicates whether the percentage of daily ED visits related to a respiratory illness are significantly increasing, decreasing or remaining stable. If there is a significant increase or decrease in the trend for a particular disease on any day of the previous week, it will be shown on this dashboard.

To determine the trend, a rolling binomial model was fit to daily ED visit data from the Centers for Disease Control and Prevention's Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE).

Data Sources

Spokane County ED visit data are gathered from ESSENCE.

Influenza hospitalization data are reported by local hospitals, and outbreak data are reported by long-term care facilities.

Influenza and COVID-19 mortality and outbreak data, as well as COVID-19 hospitalization data, are sourced from the Washington Disease Reporting System (WDRS). Because respiratory syncytial virus (RSV) is not currently a reportable condition, the dashboard does not include RSV hospitalizations, deaths or outbreaks.

The wastewater respiratory disease surveillance data for Spokane County is sourced from the Washington State Department of Health, in partnership with local water reclamation facilities. These data are normalized based on the size of the population served and number of viral gene particles detected.

Hospitalizations, Mortality and Outbreaks

Respiratory illness transmission is likely much higher than what is depicted in these visualizations. The visualizations represent more severe cases of COVID-19, influenza or RSV that result in ED visits, hospitalizations or deaths. It is very difficult to know exactly how many people in Spokane County have been infected to date since most people experience mild illness and may not seek a provider for testing.

COVID-19 hospitalization: Any inpatient hospital visit where COVID-19 is included in the diagnosis.

COVID-19 death: Any death in which COVID-19 or similar terms are mentioned on the death certificate, whether as a primary cause or contributing factor, is considered in the count.

Long-term care facility COVID-19 outbreak: As of Jan. 1, 2024, a COVID-19 outbreak in a long-term care facility (LTCF) is defined as

• ≥2 epidemiologically linked cases of COVID-19 among residents within 7 days¹, OR

• ≥2 epidemiologically linked COVID-19 cases among Health Care Personnel (HCP), AND

• ≥1 case of COVID-19 among residents, AND

• no other more likely sources of exposure for at least 1 of the cases.

This is a change from the previous, more sensitive, COVID-19 outbreak definition of one case in a resident or two epidemiologically linked staff cases over a 14-day period.

Influenza hospitalization: Any inpatient hospital visit where influenza is included in the diagnosis.

Influenza death: A laboratory-confirmed influenza-associated death is defined as a death resulting directly or indirectly from a clinically compatible illness that was confirmed to be influenza by an appropriate laboratory test. There should be no period of complete recovery between the illness and death. Laboratory criteria for diagnosis include:

• Influenza virus isolation in tissue cell culture from respiratory specimens

• Reverse-transcriptase polymerase chain reaction (RT-PCR) testing of respiratory specimens

• Immunofluorescent antibody staining (direct or indirect) of respiratory specimens

• Rapid influenza diagnostic testing of respiratory specimens

• Immunohistochemical (IHC) staining for influenza viral antigens in respiratory tract tissue from autopsy specimens

• Four-fold rise in influenza hemagglutination inhibition (HI) antibody titer in paired acute and convalescent sera

Long-term care facility influenza outbreak: An influenza outbreak is defined as: a sudden increase in acute febrile respiratory illness over the normal background rate in an institutional setting or when any resident of a long-term care facility (LTCF) tests positive for influenza.

¹ Washington State Department of Health. Interim COVID-19 Outbreak Definition for Healthcare Settings. January 25, 2024. https://doh.wa.gov/sites/default/files/2022-09/InterimCOVID-HCOutbreak.pdf