“RSV is commonly regarded as an infection typical of children,” Nicola Veronese, MD, and colleagues wrote. “Unlike influenza, for which the epidemiological importance has been widely recognized for years, the epidemiological impact of RSV infection in middle-aged and older adults has only recently gained importance. … Such as for influenza, older adults may have a greater incidence of negative outcomes when affected by RSV, since they are affected more frequently from respiratory and cardio-vascular conditions, such as [COPD] or heart
failure, which can further increase hospitalization and mortality rates and other negative outcomes”.

For a study published in Vaccines, Dr. Veronese and colleagues compared hospitalization and mortality rates associated with RSV with those associated with influenza.

“Our study is the first review systematically indicating the epidemiological importance of RSV in older people,” he said. “In particular, our results indicate that RSV could have the same impact on mortality and hospitalization as influenza, highlighting the need to identify when an older person is affected by RSV.”

The study team performed a systematic literature search and meta-analysis that included observational studies examining the rate of hospitalization and/or mortality in older people with RSV from database inception to June 15, 2022. Eligible studies included those with participants aged 60 and older, participants affected by RSV versus participants affected by influenza or healthy controls, and those including information on hospitalization and/or mortality outcomes.

RSV Hospitalization & Mortality Risk Similar to Influenza

Of 2,295 records initially included in the search, 74 were returned as full-text items. Studies were excluded if Dr. Veronese and colleagues could not conduct a meta-analysis of the results. This yielded a total of 16 studies.

The studies included 762,084 older participants (mean age, 73.4). The diagnosis of RSV/influenza was made primarily using PCR, which was sometimes done in conjunction with other diagnostic tools.

The researchers observed no significant differences between the risk for hospitalization among patients with RSV compared with patients with influenza. When considering cumulative occurrence, the risk ratio (RR) was 0.93 (95% CI, 0.53-1.62) across five studies. Results of the Egger’s test indicated the absence of any publication bias, according to the researchers.

In examining the 10 studies that included data as incidence rate per 100,000 person-years, there was again no difference seen in hospitalization rates for patients diagnosed with RSV and those diagnosed with influenza (mean difference [MD] = −262; 95% CI, −755 to 229).

The study described similar results when mortality was examined. Across four studies, RSV was not associated with any significant
increased risk for mortality when compared with influenza (RR=1.19; 95% CI, 0.98-1.45). When applying incidence rate instead of cumulative incidence, the researchers found that RSV did not differ from influenza in terms of mortality rate (MD=15 per 1,000 person-years; 95% CI, −133 to 162).

A ‘Highly Problematic Pathogen’ for Older Adults

The results indicate similar rates of hospitalizations and mortality between RSV and influenza among older adults, which—in turn—suggests the importance of vaccination for RSV in older people, according to Dr. Veronese. “Since RSV is highly prevalent in older people and associated with negative outcomes, our systematic review supports the need for increasing awareness of this phenomenon before vaccines for RSV become available,” he said.

The next “logical step” in this research “is to verify whether vaccination against RSV could be used in older people,” Dr. Veronese continued, and to determine its efficacy and safety.

“The majority of the studies regarding RSV vaccination are done among children and adults, but some promising results are showing the importance of vaccination in older people,” he said.

Dr. Veronese hopes the findings will help to highlight the prevalence and potential dangers of RSV in the older population. “A take-home
message of our investigation is to understand that RSV is a highly problematic pathogen among older people,” he noted. “Therefore, we strongly recommend that clinicians do not undervalue its role as a respiratory pathogen. Practically speaking, RSV is not present only in children; it is also important in older people.”