Respiratory virus dashboard

Deaths

A death resulting from a clinically compatible illness in a laboratory-confirmed influenza case, a laboratory-confirmed COVID-19 case, or a laboratory-confirmed RSV case unless there is a clear alternative cause of death identified (e.g. trauma, poisoning, drug overdose, etc.).

A Medical Officer of Health or relevant public health authority may use their discretion when determining if a death was due to influenza, RSV or COVID-19, and their judgement will supersede the above criteria.

A death due to influenza, COVID-19 or RSV may be attributed when influenza, COVID-19 or RSV is the cause of death or is a contributing factor.

Two Metrics Related to Hospitalizations

We use two different measures to report on hospital use for respiratory viruses. The measure of totals “in hospital and in ICU” gives an approximation of the number of people in acute care because of respiratory viruses at a point in time. The measure of total “new hospital and ICU admissions” gives an approximation of how many new patients are admitted during a particular week who require hospital care related to the respiratory virus. We detail each distinct measure below.

Totals of In Hospital and In ICU
This metric is a count of who is in the hospital or in ICU on the last day of the reporting period, regardless of when they were admitted. An aggregate count could include people who are newly admitted or who may have been in hospital for several days or weeks. The count is found on the Highlights tab. We report both the total count of all people in hospital that day (ICU and non-ICU) and the count of just those in the ICU.

AH identifies who is in hospital or in ICU for disease-related reasons by linking lab-confirmed cases of COVID-19, RSV, and influenza to hospital census administrative data to identify hospital admissions for the case. Cases are also linked to severe outcomes case reports to identify cases that were admitted to hospital or ICU for disease-related reasons. Hospital admissions that occur within 30 days of a person’s specimen collected date are assessed, or for hospital acquired infections, a person’s disease-related time in hospital starts on their specimen collected date. A person is included until their hospital discharge date or for a maximum of 60 days if the person remains in hospital. AHS conducted a chart-review of long-stay COVID-19 patients and concluded that more then 90% of patients still in hospital 45 days following their COVID-19 admission were no longer receiving care related to the COVID-19 illness.This maximum stay was implemented to minimize the inclusion of patients awaiting transfer and to more accurately reflect disease burden in hospitals. Hospital census data is provided by AHS and severe outcomes case reports are submitted to AH by AHS and FNIHB. Case reports that are submitted to AH, which include data on reason for hospital and ICU admission can have reporting delays as manual follow up of these cases by case investigators is required. Data for the previous week may be incomplete and should be interpreted with caution.

New Hospital and ICU Admissions
This metric is a count of the total number of people newly admitted to hospital or ICU for disease-related reasons for a particular week and is reported in the Severe Outcomes tab.

A hospital or ICU admission in a laboratory-confirmed influenza case, a laboratory-confirmed COVID-19 case or a laboratory-confirmed RSV case is counted when the reason for admission is either directly resulting from the disease, or when the disease is a contributing factor for the admission. Hospital and ICU admissions are identified using severe outcomes case reports which are submitted to AH by AHS and FNIHB. These case reports include reason for hospital and/or ICU admission. Reason for hospital and ICU admission was not collected for COVID-19 cases prior to 2022-02-01. Case reports that are submitted to AH can have reporting delays as manual follow up of these cases by case investigators is required. Data for the previous week may be incomplete and should be interpreted with caution as updates may occur in the following weeks as case report forms are submitted by AHS.

Coinfections

People with coinfections/mixed infections (e.g. diagnosed with both influenza A (H1N1) and COVID-19) will be counted towards each total for which they have a positive lab result. Because of these coinfections, the total number of people with COVID-19, influenza and RSV may be lower than the total number of cases, hospitalizations, ICU admissions and deaths. It may not be possible to determine if the reason for hospitalization, ICU admission or death was attributed to a particular virus. For this reason, a person with a severe outcome (hospitalization, ICU admission or death) may contribute to the total for more than one disease.

Outbreaks

Outbreaks that occur in group settings such as hospitals, residential institutions, schools, and child care facilities are reported to Alberta Health. Outbreaks are defined as the occurrence of a communicable disease in a community, region, or setting where the number of cases is more than would be expected for a defined period of time. Outbreaks in hospitals, residential institutions, and other closed communities are defined as two or more cases of influenza-like illness, with at least one laboratory-confirmed case for the disease type. School influenza outbreaks require greater than 10 per cent absenteeism or absenteeism that is 10 per cent higher than baseline levels. Please see the Public Health Disease Management Guidelines: Influenza, Seasonal and Public Health Disease Management Guidelines: Epidemics for more information.

Lab Testing

Percent positivity in Alberta is calculated using the Test Over Test method, which is the same method employed by the US Centers for Disease Control and Prevention. The calculation is as follows:

Daily Number of Positive Tests / (Daily Number of Positive Tests + Daily Number of Negative Tests)

Not all respiratory viruses are tested in all circumstances. Respiratory viruses other than COVID-19, RSV and influenza are only tested on a respiratory pathogen panel (RPP) in certain circumstances, including during outbreaks, when someone is admitted to ICU, or in instances where a physician is participating in a sentinel surveillance program.

Immunization coverage

Individuals who received one dose was calculated as (# of individuals who received at least one dose in the current season) / (population estimate).