Activity Summary
The respiratory virus activity level categorizes the percentage of emergency department (ED) visits for influenza, COVID-19, and RSV into five activity levels. These activity levels are very low, low, moderate, high, and very high. This uses methodologies adopted from U.S. CDC's Level of Respiratory Illness Activity.
The snapshot shows the trajectory classifications of three key domains, including ED visits, hospitalizations, and deaths. These domains are classified as increasing, decreasing, or remaining stable for the currently reported week compared to the previous week. The standard deviation (SD) for week-over-week difference was calculated for the previous two seasons. When the week-over-week change is positive and greater than 0.75 of the calculated SD, the trajectory is classified as increasing. When the week-over-week change is negative and greater than 0.75 of the calculated SD, the trajectory is classified as decreasing. All other week-over-week changes are classified as stable.
Syndromic Surveillance
Maine CDC analyzes diagnosis codes from visits to all EDs and some associated urgent care facilities in Maine (except Togas VA Hospital). For the respiratory virus disease dashboard, Maine CDC uses diagnosis codes reported by the hospitals to determine if each visit is due to illness with a respiratory virus. The data are displayed as the percentage of visits due to influenza, COVID-19, or RSV out of the total number of all-cause visits. County-level data are determined by the patient's residency. Patients with an unknown or out-of-state residency are not included in the county-level data but are included in statewide data.
Hospitalizations
The U.S. CDC National Healthcare Safety Network (NHSN) provides hospitalization data. This data shows the number of people admitted to hospitals for different causes. Maine CDC gets hospital admission data in Maine for COVID-19, influenza, and RSV.
Visit U.S. CDC NHSN for more information, including protocol and data collection.
Pneumonia, Influenza, and COVID-19 (PIC) Deaths
Maine uses the Electronic Death Registry System (EDRS) for death data. This system provides the number of death certificates that list certain causes of death, including death certificates which list pneumonia, influenza, and/or COVID-19 (PIC) as a cause of death. Maine CDC uses this data to calculate the percent of deaths attributed to PIC by week of death. The graphs show these numbers as unweighted percentages (number of deaths attributed to PIC/total number of deaths). Deaths related to influenza and COVID-19 are often a result of pneumonia. Calculating PIC deaths together gives a better understanding of the true impact of respiratory illness on death. The graphs show the number of deaths attributed to influenza and COVID-19 each week separately. The mean and median ages at death are calculated for the current season. These highlight different aspects of the data: the mean reflects the overall average, while the median shows the typical age at death.
Pediatric Influenza-Associated and COVID-19-Associated Deaths
Maine CDC requires providers to report pediatric lab-confirmed influenza-associated and COVID-19-associated deaths. This means for all persons less than 18 years old. Maine CDC investigates each report for demographic and clinical information. Pediatric influenza-associated and COVID-19-associated deaths are confirmed based on laboratory information and influenza or COVID-19 may or may not be listed on the death certificate. Therefore, pediatric influenza-associated and COVID-19-associated deaths may not be included in PIC deaths.
Outbreaks
Facilities are required to report all outbreaks to Maine CDC. Outbreaks are displayed by the week that they were reported to Maine CDC. The definition used to recognize outbreaks differs by setting and disease.
| Facility Type | Influenza or Influenza-Like Illness (ILI) | COVID-19 | RSV |
|---|---|---|---|
| Long-Term Care | At least one laboratory-confirmed case in the setting of a cluster (≥2 cases) of acute respiratory illness among residents within a 72-hour period. | Greater than or equal to 5 COVID-19 cases from different households, in a single setting within a 14-day period. | At least one laboratory-confirmed case in the setting of a cluster (≥2 cases) of acute respiratory illness among residents within a 72-hour period. |
| Acute Care/Nosocomial (hospital acquired) | At least one laboratory-confirmed case in the setting of ≥3 cases of acute respiratory illness among patients, where illness was not present on admission, or a combination of patients and health care workers within a 72-hour period in the same unit/wing. | Greater than or equal to 5 COVID-19 cases from different households, in a single setting within a 14-day period. | At least one laboratory-confirmed case in the setting of ≥3 cases of acute respiratory illness among patients, where illness was not present on admission, or a combination of patients and health care workers within a 72-hour period in the same unit/wing. |
| School (K-12) | Greater than or equal to 15% absenteeism among students in a single day where the majority of those absent report respiratory symptoms and influenza has been confirmed in at least one person. | Greater than or equal to 15% absenteeism among students or staff in a single day where the majority of those absent are due to COVID-19 illness and no other etiology has been identified. | Greater than or equal to 15% absenteeism among students in a single day where the majority of those absent report respiratory symptoms and RSV has been confirmed in at least one person. |
| Childcare | Greater than or equal to 15% absenteeism among students in a single day where the majority of those absent report respiratory symptoms and influenza has been confirmed in at least one person. | Greater than or equal to 5 COVID-19 cases from different households, in a single setting within a 14-day period. | Greater than or equal to 15% absenteeism among students in a single day where the majority of those absent report respiratory symptoms and RSV has been confirmed in at least one person. |
| Non-Health Care Congregate Residential Facility with a closed population (prisons, assisted living facilities, group homes, etc.) | At least one laboratory-confirmed case in the setting of a cluster (≥2 cases) of acute respiratory illness within a 72-hour period. | Greater than or equal to 5 COVID-19 cases from different households, in a single setting within a 14-day period. | At least one laboratory-confirmed case in the setting of a cluster (≥2 cases) of acute respiratory illness within a 72-hour period. |
| Non-Health Care Congregate Residential Facility with an open population (jails, shelters, dormitories, etc.) | At least 3 or more laboratory-confirmed cases who became ill within a 72-hour period. | Greater than or equal to 5 COVID-19 cases from different households, in a single setting within a 14-day period. | At least 3 or more laboratory-confirmed cases who became ill within a 72-hour period. |
NREVSS
The National Respiratory and Enteric Virus Surveillance System (NREVSS) is a laboratory-based system. It monitors respiratory and enteric virus activity. The labs in the system are part of university and community hospitals, state and county public health departments, and commercial labs. Each week, participating labs voluntarily report:
- The total number of tests performed
- The test type used for detection
- The number of those tests with positive results
The graphs show influenza, COVID-19, and RSV data from laboratories in Maine.
Influenza Laboratory Tests Reported to Maine CDC
Maine CDC does not require labs to report influenza results. This means the number of reported positive test results does not reflect the total amount of influenza in Maine. These data do provide information about the influenza viruses circulating in Maine. They also help show the presence and define the distribution of influenza in the state.
Maine Health and Environmental Testing Laboratory (HETL)
Hospitals and clinical laboratories in the state work with HETL to submit specimens. HETL tests these for respiratory viruses and influenza subtyping year-round. This testing is important in identifying the circulating influenza viruses. It also confirms specimens that tested positive by rapid test.
COVID-19 Cases
Maine CDC requires providers to report all positive COVID-19 laboratory results for CLIA-approved lab tests. Maine CDC classifies COVID-19 cases based on testing method. Confirmed cases are those with a positive SARS-CoV-2 molecular test, like PCR. Probable cases are those with a positive SARS-CoV-2 antigen test. The graph shows cases by the week the specimen was collected.