Good flu vaccine can reduce nursing home residents' hospitalizations

By Shannon Aymes

New York (Reuters Health) - A well-matched influenza vaccine may prevent some pneumonia- and influenza-associated hospitalizations and deaths among nursing home residents, according to a new study.

"Over the last years it has been unclear whether the flu vaccine is really effective in patients of advanced age. It is generally thought that older people, especially those with multiple chronic medical problems, do not respond to vaccines as well as younger people," Dr. Aurora Pop-Vicas from Warren Alpert Medical School, Brown University in Providence, Rhode Island, told Reuters Health by email.

"On the other hand," she said, "the flu vaccine is universally recommended for all ages, and is actually an indicator of health care quality in the nursing home setting. Thus, it was important to study how effective the flu vaccine actually is in preventing morbidity and mortality in the nursing home setting."

Dr. Pop-Vicas and colleagues wanted to estimate how effective influenza vaccines are on nursing home residents with respect to deaths and hospitalizations.

They conducted a retrospective cohort study of nursing home residents in cities that were under surveillance by the Centers for Disease Control and Prevention (CDC) for influenza. Between October 2000 and March of 2009, data was collected on each nursing home facility for Medicare hospital claims and dates of death.

During the study period, the match rate between the flu vaccine and A/H1N1 was high except for one season. Furthermore, the match rate for A/H3N2 was quite variable and overall low for the B-strain, according to an article online August 17 in the Journal of the American Geriatrics Society.

Pneumonia- and influenza-related hospitalizations were found to be higher in years where A/H3N2 was highly prevalent and there was a poor flu vaccine match. However, this relationship was not found in years with a good vaccine match.

Furthermore, after controlling for the match rate, a higher rate of flu vaccination was associated with lower pneumonia- and influenza-related hospitalizations and death.

Prediction models estimated that every 1% increase in vaccination rate could translate into two fewer hospitalizations and 1.6 fewer deaths in nursing home residents.

Furthermore, they calculated that 100 fewer hospitalizations and 80 fewer deaths would occur per nonsummer week in years with a good vaccine match to A/H3N2 versus a year with a poor match.

Over the course of a 32-week influenza season it would add up to 3,200 fewer hospitalizations and 2,560 fewer deaths. Therefore, an increase in the A/H3N2 match rate by 50% could decrease pneumonia and influenza hospitalizations by 4.2% and deaths by 2.0%.

"Physicians should know that if the flu vaccine is well matched to the circulating strains during the flu season, it can still offer protection from influenza-related severe complications and deaths even to the frailest elderly people," Dr. Pop-Vicas said.

"Of course, as physicians we have a double responsibility: to offer the flu vaccine to our patients, and to vaccinate ourselves in order to further protect our most vulnerable patients from the deleterious effects of the flu," she further noted.

Dr. David H. Howard, of the Department of Health Policy and Management at Emory University in Atlanta, noted in an email to Reuters Health, "Nursing homes do a pretty good job of vaccinating residents, but there are still about 20%-25% of residents who are not vaccinated. We need to know: How much effort should nursing homes exert to promote vaccination to residents (and their families)?"

"This is an important study because it provides novel evidence on the value of influenza vaccination among nursing home residents. Influenza vaccine isn't perfect, but it is effective in preventing death and hospitalization among elderly people," Dr. Howard continued.

The study was supported by a grant from the Agency for Health Care Research and Quality. The authors reported no conflicts of interest.

SOURCE: http://bit.ly/1MP6gF3

J Am Geriatr Soc 2015.

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