Like an unwelcome guest, the 2018-2019 flu season seems to be settling in for a lengthy stay as three more states have reached the highest level of influenza-like illness (ILI) activity, according to the Centers for Disease Control and Prevention.
There are now 21 states at level 10 on the CDC’s 1-10 scale, with the South showing up almost solidly red on the flu activity map for the week ending Feb. 9. Another five states are at levels 8 and 9, bringing the total in the high range to 26 for the week, compared with 24 the previous week, the CDC’s influenza division reported Feb. 15.
National activity, reflected in the proportion of outpatient visits involving ILI, took a step up from 4.3% the week before to 4.8% for the week ending Feb. 9. The national baseline rate is 2.2% for ILI, which the CDC defines “as fever (temperature of 100°F [37.8°C] or greater) and cough and/or sore throat.”
Two flu-related pediatric deaths occurred during the week ending Feb. 9, and another four were reported from earlier weeks, which brings the total for the 2018-2019 season to 34, the CDC said. At the same point in last year’s flu season, there had been 84 flu-related deaths in children.
In a separate report, the CDC said that, based on data collected from Nov. 23, 2018 to Feb. 2, 2019, “the influenza vaccine has been 47% effective in preventing medically attended acute respiratory virus infection across all age groups and specifically was 46% effective in preventing medical visits associated with influenza A(H1N1)pdm09.” The effectiveness of the vaccine was 61% for children aged 6 months to 17 years, the CDC said (MMWR. 2019 Feb 15;68;135-9).
Flu vaccination during the 2017-2018 season prevented 7.1 million illnesses, 3.7 million medical visits, 109,000 hospitalizations, and 8,000 flu-related deaths, the CDC said, adding that “vaccination has been found to reduce deaths, intensive care unit admissions and length of stay, and overall duration of hospitalization among hospitalized influenza patients.”
Forecasts for the rest of the 2018-2019 season “predict that elevated influenza activity in parts of the United States will continue for several more weeks,” the CDC said.