In findings that should give pause to parents declining to immunize their children for flu out of misplaced fear of vaccine safety, researchers have found evidence that flu shots in pediatric patients can be literally lifesaving.
The findings suggest flu vaccination “reduced the risk of influenza-associated death by half among children with high-risk conditions and by nearly two-thirds among children without high-risk conditions,” the authors reported in a new study.1
The study, which was conducted by CDC investigators, is the first to use laboratory-confirmed outcomes to determine flu vaccine efficacy against influenza-associated deaths, the authors report, noting that “observational studies that have used nonspecific outcomes, such as all-cause mortality, have often overestimated effects of influenza vaccination on mortality in older adults.”
The researchers conducted a case–cohort analysis comparing vaccination uptake among laboratory-confirmed influenza-associated pediatric deaths with estimated vaccination coverage among pediatric cohorts in the United States. From July 2010 to June 2014, 358 laboratory-confirmed influenza-associated pediatric deaths were reported among children 6 months to 17 years old. Vaccination status was determined for 291 deaths; 75 (26%) received vaccine before illness onset. Average vaccination coverage in survey cohorts was 48%. Overall vaccine efficacy against death was 65%. Among 153 deaths in children with underlying high-risk medical conditions, 47 (31%) were vaccinated. Vaccine efficacy among children with high-risk conditions was 51%, suggesting it may be particularly important to immunize this group, they noted.
“Despite high prevalence (53%) of underlying conditions that increase risk of severe influenza-related complications, only 1 in 4 children who died with laboratory-confirmed influenza had been vaccinated,” the authors concluded. “These results reinforce the need to increase influenza vaccination coverage, especially among children at increased risk of influenza-related complications and death.”
Annual influenza vaccination beginning at six months of age is recommended to prevent influenza and its complications. From 1976 to 2007, pediatric influenza was estimated to cause some 100 deaths annually, the authors report. Since 2004, when influenza-associated deaths among children under 18 became nationally notifiable, reported numbers of deaths have ranged from 37 in the 2011–2012 season to 358 during the 2009 H1N1 influenza A pandemic, they noted.
Variations Among Job Roles
In another new flu study2 that will inform vaccination strategies for both seasonal illness and the next pandemic, researchers found that immunization varied widely over various job categories. Seasonal flu vaccination was particularly low in some occupations that have a high level of public contact and interaction.
“Influenza vaccination coverage was less than 30% among some occupations with frequent contact with the public, such as food preparation and serving, sales, personal care, and service occupations, even though there have been relatively high rates of influenza-like illness documented in these occupations,” the researchers reported. “Influenza vaccination has been shown to be cost-effective and inexpensive for large employers, and offering vaccination in workplaces where coverage is low may increase coverage rates in these groups.”
Data from 21 states using the 2013 Behavioral Risk Factor Surveillance System industry occupation module were analyzed. Using this data set and broadening the definition resulted in a much lower immunization rate than the 91% reported for hospital workers by the CDC.3 (See Hospital Infection Control & Prevention, November 2016.)
In the new study, “healthcare practitioners” and “allied technical workers” had a flu immunization rate of 62%, which was still higher than the other occupations examined. For example, only 19% of construction workers received the influenza vaccination, making them the least immunized work force studied.
Based on their experience with the 2009 influenza A (H1N1) pandemic, 35% of “immunization program managers” said they would change their vaccine allocation strategy, the authors reported. One area to be resolved was whether high priority healthcare personnel should be expanded to include firefighters, police, school nurses, and teachers.
The study was published in the peer reviewed journal of the Association for Professionals in Infection Control and Epidemiology (APIC).
“Studying areas in need of improvement in infection prevention is critically important for public health,” Linda Greene, RN, MPS, CIC, FAPIC, president of APIC, said in a statement. “Healthcare personnel and those in frequent contact with high-risk groups must be encouraged to take all necessary steps to prevent spreading any type of illness, including getting annual flu shots.”
REFERENCES
- Flannery B, Reynolds SB, Blanton L, et al. Influenza Vaccine Effectiveness Against Pediatric Deaths: 2010–2014. Pediatrics 2017: http://bit.ly/2nFgM7x
- O’Halloran AC, Lu, PJ, Williams, W, et al. Influenza vaccination among workers—21 U.S. states, 2013. AJIC 2017; 45:410-416.
- CDC Influenza Vaccination Coverage Among Health Care Personnel — United States, 2015–16 Influenza Season. MMWR 2016; 65(38):1026–1031.
