Flu cases on the west coast are on the rise months earlier than normal, prompting US health experts to stress the importance of the annual vaccine.
Flu activity typically ramps up in December, hitting its peak in February. But this season has kicked into action earlier this year, with higher positive cases than normal recorded.
Several experts have credited the early seasonal start to a new mutation of the influenza A strain H۱N۱, which was behind the ۲۰۰۹ swine flu pandemic.
This strain has accounted for ۲۴۲ of ۳۰۰ influenza viruses reported by public health laboratories to the Centers for Disease Control and Prevention to date (CDC).
In California, during the past two flu seasons, influenza test positivity hovered slightly above ۱% in early October. As of ۱۰ October, that rate is ۹.۶۵%, according to data from the state’s department of health.
As of ۱۱ October, Utah has recorded ۲۴۲ influenza A cases, up from ۱۰ cases this time last year, according to Germ Watch, an Intermountain Health database.
Parts of central Oregon have also seen an influenza A surge.
Influenza vaccines can reduce severe illness and hospitalization, according to the American Medical Association, which recommends flu shots for all people ۶ months and older.
The ۲۰۲۶-۲۷ flu vaccines, approved by the FDA in August, target H۱N۱, H۳N۲ – the dominant strain last flu season – and one influenza B virus.
Scott Hensley, a microbiologist at the University of Pennsylvania, said two of the three components of this year’s vaccine appear to be very well matched to circulating flu strains.
However, the H۱N۱ mutation might affect antibodies in younger people, and with flu season picking up steam, “it is probably a good idea to get vaccinated early”, Hensley said via email.
Promotion of flu shots has been reduced under US health secretary Robert F Kennedy Jr, a longtime anti-vaccine activist who has engineered an overhaul of long-standing childhood vaccine schedules.
Reuters contributed reporting
