While flu cases have remained remarkably low throughout this season, the most dominant strain is a variant of the influenza A virus, the influenza virus most commonly known to cause flu pandemics, according to information provided by the US CDC.
The most prominent influenza A variant this season is the H3N2, which is associated with increased influenza morbidity and mortality, according to data from the CDC’s weekly FluView report.
“Of all the influenza viruses that routinely circulate and cause illness in people, influenza A (H3N2) viruses tend to change more rapidly, both genetically and antigenically. Influenza A (H3N2) viruses have formed many separate, genetically different clades in recent years that continue to co-circulate,” the CDC says.
Overall, influenza activity is barely detectable in much of the country. Only 0.2% respiratory samples tested for flu this year have come back positive for any strain, a significantly lower rate than usual. Out of the 9,412 samples tested during the last week of March, only one flu case was identified, signaling that most suspected flu cases may be due to the novel coronavirus.
Nationwide, 0.9% of patient visits during the last week of March were attributed to influenza-like symptoms, which is less than half of the typical baseline of 2.6%. All regions throughout the Untied States reported a low number of healthcare office visits for influenza-like symptoms.
“Healthcare-seeking behaviors have changed dramatically during the COVID-19 pandemic. Many people are accessing the healthcare system in alternative settings, which may or may not be captured,” the CDC reported.