Recently published research shows that laboratory-confirmed influenza infection resulted in 45% more missed work hours and more severe illness than acute respiratory infections not confirmed as influenza, although the latter can be drastically reduced with vaccination, as reported by Healio. Joshua G. Petrie, MPH, and colleagues write, “With the development of real-time reverse-transcriptase PCR [RT-PCR] assays, we are now able to identify precisely those illnesses that are potentially vaccine-preventable. We can also compare the severity of illnesses laboratory-confirmed as influenza to those that are not.”
Petrie and fellow researchers examined a cohort of 1,548 working adult patients with medically attended acute respiratory illnesses (MAARI) who participated in the US Flu Vaccine Effectiveness Network study during the 2012-2013 influenza season, according to Healio. The patients included were employed and worked 20 or more hours a week and had RT-PCR testing, vaccination, and outcome data readily available. Demographic characteristics, productivity impairment information, and subjective self-assessments were collected at enrollment and via a follow-up survey completed 7 to 21 days after illness.
Using the collected data, the researchers compared illness severity and hours of work missed between participants with and without lab-confirmed influenza as well as between those with influenza who did and did not receive seasonal vaccination. About 38% of participants with MAARI tested positive for influenza type A (H3N2), according to researchers, and MAARI cases that tested positive for influenza believed themselves to be less healthy than non-influenza cases upon enrollment. They also reported reduced sleep quality and ability to perform normal activities as well.
Influenza cases reported missing an average of 20.5 work hours due to their illness compared with an average of 15 hours reported by those without influenza. The research team writes, “These findings are consistent with the results of previous studies that indicated influenza illnesses were more likely to be medically attended than illnesses caused by other respiratory viruses, and that those infected with influenza had higher illness severity scores than those with non-influenza acute respiratory illness.”
The impact of influenza on MAARI patients seemed to be diminished by previous vaccination, researchers write, as participants with influenza were more likely than those without to have documented evidence of influenza vaccination, as indicated on the Healio news report. Health status reported at enrollment and ability to perform normal activity were both greater for vaccinated cases of influenza, as opposed to unvaccinated cases.
“Due to the substantial economic and personal burden of acute respiratory illnesses including influenza, there are clear benefits to be gained by effective prevention and treatment strategies,” the researchers write. “These findings confirm the potential value and economic benefit of vaccination and illustrate the importance of laboratory-confirmation of influenza outcomes in evaluations of vaccine effectiveness.”