CDC Influenza Update for Geriatricians and Other Clinicians Caring for People 65 and Older

2012-2013 Influenza Season, Impact on the Elderly, Summary Guidance

January 23, 2013

Background

It has been recognized for many years that people 65 years and older are at greater risk of serious complications from influenza compared with young, healthy adults. It's estimated that 90 percent of seasonal influenza-related deaths and more than 60 percent of seasonal influenza-related hospitalizations in the United States each year occur in people 65 years and older. Hospitalizations also are often sentinel events in this group of people, precipitating disability, and potentially resulting in loss of the ability to live independently. Preventing influenza and treating it promptly may reduce the risk of influenza-associated complications, including hospitalization and death.

Current Situation

The 2012-2013 influenza season began early and most of the country is now experiencing high or widespread influenza activity. Seasons during which influenza A (H3N2) viruses predominate are typically associated with higher rates of hospitalizations and deaths among the elderly. A review of recent surveillance data, including data from CDC’s hospitalization and death surveillance systems, indicates that this is true for the current season as well. CDC’s recommendations for prevention and treatment of influenza among persons 65 and older remain unchanged for the current season. This document contains a summary of geriatric hospitalization and death data to date this season as well as a summary of CDC’s influenza vaccine and antiviral recommendations for people in this age group.

Summary of Geriatric Hospitalization and Death Data This Season To Date

Hospitalizations: In recent weeks, the hospitalizations rates in people 65 and older increased steeply. As of January 12, the influenza-associated hospitalization rate for persons 65 and older was 82 per 100,000, an increase from 69.8 per 100,000 during the prior week. These rates are high when compared to the same time last season (which was mild), but are within what is expected for a moderately severe season. Among laboratory-confirmed influenza hospitalizations, 50% of those hospitalized have been among persons 65 and older.

Geriatric Deaths: Influenza-associated mortality indicators also increased sharply in the last two weeks, with the mortality indicator (for all ages) exceeding the epidemic threshold for the second consecutive week this season as of January 12. At that time, 80 percent of cumulative deaths had occurred in people 65 or older.

It is likely that more hospitalizations and deaths will be reported since influenza activity will probably continue in the United States for several more weeks.

CDC Recommendations

Influenza Vaccination

As always, CDC continues to recommend influenza vaccination for people who have not yet been vaccinated as long as influenza viruses are circulating. This includes people 65 and older, who have two vaccines available to them: a regular trivalent inactivated vaccine and the Fluzone High-Dose vaccine designed specifically for people age 65 years and older. Fluzone High-Dose vaccine contains a higher dose of antigen than regular influenza shots, and this may give older people a better immune response to the vaccine. The CDC and its Advisory Committee on Immunization Practices (ACIP) have not expressed a preference for either vaccine. Providers should continue vaccinating patients at this time. Those providers who have exhausted their supplies of influenza vaccine may be able to purchase additional vaccine. If unable to do so, providers should encourage their unvaccinated patients to seek influenza vaccine at other locations.

It should be noted, however, that the elderly may not respond as well to vaccination as younger persons. A recently published MMWR “Early Estimates of Seasonal Influenza Vaccine Effectiveness — United States, January 2013” found estimated overall vaccine effectiveness (VE) of 62% for preventing laboratory-confirmed influenza virus infection associated with medically-attended ARI among vaccinated persons this season. These early study results were not adjusted for age, but based on previous studies, vaccine effectiveness is expected to be lower – perhaps substantially lower – among the elderly than in the general population. Vaccination of caretakers and close contacts of seniors is especially important for this reason. Additionally, as some vaccinated persons will develop influenza, providers also are reminded of CDC’s recommendations for the use of influenza antiviral medications for treatment during the current season.

Antiviral Treatment

Antiviral treatment can reduce the duration of illness and complications associated with influenza. In outpatient settings, empiric therapy is recommended for all persons 65 and older with suspected influenza, regardless of the severity of illness. Providers should encourage their patients to seek treatment immediately after illness onset, and should prescribe antiviral medication as appropriate.

Early antiviral treatment also is recommended for all persons with suspected influenza with severe or progressive illness (e.g., hospitalized persons). Antiviral treatment should be started as early as possible, preferably within 48 hours after illness onset, but among hospitalized patients, treatment should be initiated on admission regardless of time since symptom onset. Several studies suggest that antiviral treatment reduces mortality and illness severity among hospitalized adults even when initiated ≥48 hours after illness onset. The decision to initiate antiviral treatment should be made regardless of vaccination status, should not wait for laboratory confirmation of influenza and should not be dependent on insensitive assays such as rapid influenza diagnostic tests.

In addition, CDC continues to recommend prompt recognition and management of influenza outbreaks in long-term care facilities. Elderly patients residing in long-term care facilities are vulnerable to influenza outbreaks, which in this setting may cause widespread illness with a high fatality rate. To prevent outbreaks, all long-term care facility residents and health care personnel should be vaccinated against influenza. In addition, a suspected influenza outbreak should prompt immediate action. Surveillance should be implemented to identify new cases and standard and droplet precautions should be instituted without delay. All facility residents who have confirmed or suspected influenza should receive antiviral treatment immediately without awaiting confirmatory testing. In addition, all eligible residents in the entire facility, not just the affected unit, should receive chemoprophylaxis as soon as an influenza outbreak is identified. For more details on the management of long-term care facility influenza outbreaks, please see Interim Guidance for Influenza Outbreak Management in Long-Term Care Facilities.

CDC has resources for patients available at Other Important Information for People Sick with Influenza.

CDC is actively monitoring influenza activity during the current season and publishes updates weekly at Flu Activity & Surveillance. Additional information will be provided as needed.