CDC: Most children don’t get full benefit of flu vaccine

Most children are not being adequately vaccinated against influenza, according to new data from the Centers for Disease Control and Prevention (CDC), which also just published a new report demonstrating the efficacy of the vaccine in reducing influenza-related deaths in children.

The CDC used data from the National Immunization Surveys-Flu (NIS-Flu) for the 2012 through 2014 flu seasons. Although overall flu vaccination rates from the 2016-2017 season won’t be available until fall, early season coverage estimates found that vaccination coverage among children was about 37% in November and rose to 50% by December 2016, similar to the 51% as of December 2015. Total vaccination coverage among children for the 2015-2016 flu season was 59%, according to the CDC.

Other preliminary findings show that coverage was highest for children aged 6 to 23 months at 66%, followed by 56% for children aged 2 to 4 years, 50% for children aged 5 to 12 years, and 40% for children aged 13 to 17 years.

Yusheng Zhai, MSPH, a contractor for the CDC and coauthor of a study of the new CDC data in the American Journal of Preventive Medicine, says that although about half of children in the United States get at least 1 vaccination, most children are not fully vaccinated against influenza. Roughly 2 of 5 children aged 6 months to 8 years were fully vaccinated during the 2 flu seasons studied. Most of these children-60%-required 2 doses of the influenza vaccine to be fully vaccinated, but about half received just 1 dose and only 10% were fully vaccinated.

“This finding suggests that there are barriers to receipt of the second required dose,” Zhai says. “As long as flu viruses are circulating, pediatricians should recommend and give flu vaccine to children 6 months and older. For children who will need 2 doses of flu vaccine, the first dose should be given as early in the season as possible. Reminder systems and interventions that reduce or remove barriers to children receiving their second dose of influenza vaccine, such as recall systems, text reminders, intensive outreach, and client or community-wide education may help improve the number of children who are fully vaccinated against influenza.”

There were racial and ethnic differences in full vaccination coverage that didn’t match up to 1 or more dose coverage, Zhai notes. “Non-Hispanic black children had lower full vaccination coverage compared to all of the other race/ethnicity groups in both the 2012–2013 and 2013–2014 seasons; however, black and white children had similar 1 or more dose coverage,” he says. “This suggests there may be more barriers for black children to receive their second dose.”

Zhai says the fact that so many children were vaccinated, but not fully, really surprised him. “While over 65% of children aged 6 months to 8 years received 1 or more doses of influenza vaccination during the 2 studied seasons, the full influenza vaccination rates of these children were at only 41% and 45%, respectively,” Zhai says. “Nearly 90% of children who required 2 doses of influenza vaccine to be fully protected from influenza did not receive their required second dose. More widespread use of strategies known to increase second dose vaccination rates is warranted.”

The CDC also found that 1 of the most common reasons that parents didn’t have their child vaccinated against the flu was that they believed their child wasn’t susceptible to influenza, often because their child was healthy and not in a high-risk category. Parents who didn’t vaccinate their children also often reported that the vaccine was not promoted or recommended by their child’s pediatrician.

Pediatricians play an important role in dispelling these and other myths about influenza vaccination, Zhai says. “It’s important for clinicians to emphasize that influenza can be dangerous for children. Each year, millions of children get sick with seasonal influenza; thousands of children are hospitalized and some children die from flu,” he says. “Children commonly need medical care because of influenza, especially before they turn 5 years old.”

Zhai says he hopes these updates from the CDC will prompt physicians to talk to parents about influenza vaccination.

“We hope this serves as a reminder for clinicians to ensure their patients are protected against seasonal influenza and its complications,” he says. “Some children 6 months through 8 years of age require 2 doses of influenza vaccine. Children 6 months through 8 years getting vaccinated for the first time, and those who have only previously gotten 1 dose of vaccine, should get 2 doses of flu vaccine. For children who will need 2 doses of flu vaccine, the first dose should be given as early in the season as possible.”

The Advisory Committee on Immunization Practices (ACIP) currently recommends annual influenza vaccination for everyone aged 6 months and older. Two doses given 4 weeks apart is recommended for children aged 6 months to 8 years to ensure optimal protection. This recommendation varies, and in the past, ACIP has recommended just 1 dose for children aged 6 months to 8 years if they had received a total of 2 or more doses since 2010. Over the last several seasons, about two-thirds of all children required 2 doses to be fully vaccinated, with those percentages being highest among older children, according to the report.

The CDC also recently published a study in Pediatrics demonstrating for the first time that the flu vaccine can significantly reduce mortality in pediatric flu cases.

The study examined data from 2010 to 2014 and found that flu vaccination reduced the risk of flu-associated deaths by 51% among children with underlying medical conditions and by 65% among healthy children. In total, 358 laboratory-confirmed cases of flu-associated death in children were reported to the CDC, and of the 291 with known vaccination status, only 26% of those children had been vaccinated. The report notes that so far this year, 61 pediatric deaths related to influenza have been reported to the CDC.

“Every year the CDC receives reports of children who died from the flu. This study tells us that we can prevent more of these deaths by vaccinating more,” Brendan Flannery, PhD, lead author of the study and epidemiologist in the Influenza Division at the CDC, said in a prepared statement. “We looked at 4 seasons when we know from other studies that the vaccine prevented flu illness, and we found consistent protection against flu deaths in children.”