The 2017-2018 flu season has been one of the most virulent health officials have seen in a decade and has been responsible for a high number of fatalities, including 84 children nationwide, but the peak may finally have been reached.
Cases are still spreading, but rates are dropping or at least remaining steady, which is an indication the peak of the spread of infection may have passed. Even still, the California Department of Public Health expects several more weeks of flu activity and the mortality rate could continue to climb because it can be days or weeks after the initial infection that complications can set in.
Since Oct. 1, 2017, 19,398 laboratory-confirmed influenza-associated hospitalizations have been reported through the Influenza Hospitalization Network to the Centers for Disease Control. This translates to a cumulative overall rate of 67.9 hospitalizations per 100,000 people in the United States. The highest hospitalization rate is among people 65 years and older, followed by adults aged 50-64 years, and younger children aged 0-4 years. During most seasons, adults 65 years and older have the highest hospitalization rates, followed by children 0-4 years.
In California, there have been 185 deaths of people 65 and younger, according to the latest update from the California Department of Public Health.
While seasonal flu outbreaks can happen as early as October, flu activity is usually highest between December and February, and can last through the spring. Each year, flu causes millions of illnesses, hundreds of thousands of hospitalizations and thousands or sometimes tens of thousands of deaths in the United States.
The CDC reported that the influenza A(H3N2) viruses have been predominate this season, which is problematic for health officials, because it is a strain that has in the past been responsible for more hospitalizations and deaths in people 65 years and older and younger children, according to the CDC. Additionally, the vaccine effectiveness for A(H3N2) has generally been lower than other strains. The vaccine efficacy estimates for Influenza A (H3N2) are 25 percent; for Influenza A (H1N1) are 67 percent; and for Influenza B the rates are 42 percent.
Even though this season’s vaccine is proving to be less effective than officials expected, the CDC is still recommending vaccination.
“We continue to recommend the flu vaccine even though we know most flu vaccines have low effectiveness against H3N2 viruses, effectiveness against other flu viruses is better, and there is more than one flu virus circulating this season,” said Dr. Anne Schuchat, the principle deputy director at the CDC, in a teleconference briefing. “The vaccine may also reduce the severity of symptoms if you catch the flu in spite of being vaccinated, and it is not too late to get the vaccine.”