Key Point

According to a recently published study, RSV infection appears to be of importance comparable to influenza in the elderly and high-risk adults—a finding that may warrant the development of a vaccine.

ROCHESTER, NY—Most would agree that continuing to improve the influenza vaccine and ensuring that supplies are adequate and delivered on time should remain high priorities. However, according to Ann R. Falsey, MD, and colleagues, other pathogens also contribute to the increase of patients in physicians’ offices and hospitals during the winter months. Dr. Falsey is an Associate Professor of Medicine at the University of Rochester in New York.

These other pathogens include respiratory syncytial virus (RSV), the burden of which was prospectively studied in healthy elderly individuals and high-risk adults.¹ “The results of this study document the importance of RSV infection in adults and confirm the need for the development of an RSV vaccine for high-risk and elderly adults,” said the authors.

A FOUR-YEAR STUDY

The study included 608 healthy persons 65 or older who had no disabling illnesses, 540 adults with physician-diagnosed congestive heart failure or chronic pulmonary disease (the high-risk group), and 1,388 hospitalized patients (the only group not prospectively evaluated). The mean ages in the three groups were 75, 70, and 75, respectively. Exposure to children was more likely in the high-risk group than in the healthy elderly or hospitalized groups.

During four consecutive winters, there were 1,043 illnesses in the prospectively evaluated patients and 1,471 illnesses in the hospitalized patients. “RSV infection was identified in 102 cases of illness involving patients in the prospective cohorts and in 142 cases involving hospitalized patients. Influenza A was diagnosed in 44 cases of illness involving patients in the prospective cohorts and in 154 cases involving hospitalized patients,” reported the authors.

Influenza was used as a benchmark, Dr. Falsey told Pulmonary Reviews, “because everybody appreciates that influenza is a serious disease in older people and that we need a vaccine to prevent it. We used precisely the same diagnostic tools for RSV and flu so we could compare apples to apples,” she emphasized.

INFECTION RATES SIMILAR

Annual rates of RSV infection were 3% to 7% in the healthy elderly group, 4% to 10% in the high-risk group, and 8% to 13% in the hospitalized group. The respective annual influenza A rates in the three groups were 2% to 4%, 0.4% to 5%, and 1% to 20%.

In the healthy elderly group, RSV was less likely than influenza to require professional health care. In the high-risk group, however, it was just as likely as influenza to result in a telephone call or visit to a physician, a trip to the emergency department, or hospitalization. Furthermore, RSV and influenza were associated with a similar length of stay, need for intensive care, and mortality risk in the hospitalized group.

“Overall, according to the diagnosis at discharge, RSV infection accounted for 11% of hospitalizations for pneumonia, 11% for chronic obstructive pulmonary disease, 5% for congestive heart failure, and 7% for asthma,” reported Dr. Falsey and colleagues. The disease burden of RSV would still be roughly comparable to that of influenza even if there were no influenza vaccination programs, Dr. Falsey asserted. “RSV is not an insignificant disease, and when you compare it to the flu it seems that an effective vaccine would be of benefit,” she concluded.

—Timothy Begany

Reference
1. Falsey AR, Hennessey PA, Formica MA, et al. Respiratory syncytial virus infection in elderly and high-risk adults. N Engl J Med. 2005;352:1749-1759.

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