Flu season is here, and U.S. doctors are warning it’s worst they’ve seen in 10 years

U.S. doctors are warning their colleagues about what they say are alarming increases in vaccine-preventable hospitalizations among children who have recently been vaccinated against H1N1 (swine flu) and influenza-like illness. From July 2014 to…

Flu season is here, and U.S. doctors are warning it’s worst they’ve seen in 10 years

U.S. doctors are warning their colleagues about what they say are alarming increases in vaccine-preventable hospitalizations among children who have recently been vaccinated against H1N1 (swine flu) and influenza-like illness.

From July 2014 to August 2015, two data sets of children under age 18 with recent vaccinations against H1N1 and influenza-like illness jumped about 30 percent in hospitalizations in every age group compared with the year before, a study published in JAMA Pediatrics on Monday revealed.

While a decrease in the number of hospitalizations that year was considered statistically significant, the 2017-18 season ended with greater hospitalizations than the prior year, especially in children younger than 2 years old, said Dr. Jeffrey Koplan, a vaccine researcher at the University of Nebraska Medical Center, School of Medicine, in Omaha and the study’s lead author.

For 2018, the number of hospitalizations for H1N1 and influenza-like illness among children younger than 2 year old in the two data sets were 17.4 percent and 7.6 percent higher than in 2014-15, according to the report.

In an editorial accompanying the study, Dr. Jeffrey Klausner of the University of North Carolina in Chapel Hill in Chapel Hill said the increase was a “remarkable” one and suggested that it could have implications for flu prevention.

“Given the fact that there is no way to definitively determine the rate of influenza vaccine coverage in the United States, this data is particularly concerning,” Klausner wrote. “As vaccination coverage declines in low-vaccination age groups, it seems likely that rates will remain low in high-vaccination age groups. We need to keep further population surveillance to assess whether this increase in hospitalizations are adequately associated with increasing vaccine coverage of vaccines.”

Koplan and his colleagues tracked hospitalizations in children who had previously been vaccinated against H1N1 or influenza-like illness against hospitalization rates within the five states — New Hampshire, Vermont, Maine, Connecticut and New York — that have very high vaccination rates, about 75 percent or more.

In New Hampshire, which had the highest vaccination rate in the study, the total number of hospitalizations of children previously vaccinated against H1N1 jumped a whopping 41 percent between 2015 and 2016. In Maine, which had the second-highest percentage of children who had been vaccinated, there was a 7 percent increase in H1N1 hospitalizations among children, the study reported.

The increasing number of deaths from H1N1 and influenza-like illness is a nationwide phenomenon, experts said. Deaths from other kinds of influenza, including H3N2 and influenza B, decreased by 1.7 percent over the past two seasons, the study found.

Fauci acknowledged the “small uptick” in hospitalizations this season but said the findings did not change the way the federal government views the positive safety benefits of immunizing children against H1N1 and influenza-like illness.

“There are some safety indicators that we can track, so the overall safety profile of H1N1 remains very good,” he said in an interview, noting that most children in hospitalized for those two conditions are experiencing flu-like symptoms and not H1N1.

Koplan and his colleagues note in their study that the authors knew the age, sex and race of the children, a potentially important predictor of safety. In the analysis, they included 35 percent black and 24 percent Hispanic children who had not previously been vaccinated against H1N1 and influenza-like illness.

“In our observational study, data was available for all children and we only included those with illness,” the researchers wrote.

The Kaiser Permanente Childhood Health Study (CMS) has been tracking the health of children born from 1991 to 1994 and children under 5 from 1999 to 2010.

— Andrew M. Weil, Washington Post

Leave a Comment