Flu Cases Exceed 22 Million in US, CDC Reports

An original version of this article was published by sister publication ContagionLive.

Although much attention has been on novel coronavirus (COVID-19), due to an increasing number of cases across the globe, the numbers indicate that we need to continue to pay attention to influenza (flu).

Only 13 cases of the COVID-19 have been confirmed in the US, yet flu cases for the 2019-20 US season have topped 22 million—an increase of 4 million cases over a one-week span. And flu activity will only continue to increase in the upcoming weeks.

The US Centers for Disease Control and Prevention’s (CDC) FluView reports that last week the percentage of deaths attributed to pneumonia and influenza stands at 7.1%, just below the epidemic threshold of 7.2%.

Visits to clinicians for influenza-like illness increased from 6% to 6.7% last week with all regions remaining above baseline. However, overall hospitalization rates for the season are similar to previous seasons with a current rate of 35.5 per 100,000.

The percentage of respiratory specimens testing positive for influenza at clinical laboratories also increased last week, rising from 28.4% to 29.8%. At this time, 47 jurisdictions are experiencing high influenza-like illness activity, compared with 44 jurisdictions the previous week.

Recent estimates indicate that of the 22 million flu cases in the US thus far, 210,000 hospitalizations have occurred, and 12,000 deaths have been reported. In total, there have been 78 pediatric deaths so far this season, with 10 new deaths reported last week.

Earlier this season it was reported that influenza B/Victoria was the predominant strain for the 2019-20 season, yet at this time cases of the A(H1N1)pdm09 virus are approximately equal to the B strain after rising over recent weeks.

CDC officials continue to recommend vaccination as the best way to prevent influenza and reduce duration of illness. According to the agency, approximately 173.3 million doses of the flu vaccine have been administered in the US this season.

“I think something that gets lost in the narrative is that while the flu shot prevents a percentage of infections, and some people will go and develop the flu anyway, even if they do, there's some evidence that it's attenuated, and that the complications from having the flu including death are lessened even if someone develops flu after they've gotten a shot,” Jason C. Gallagher, PharmD, editor in chief of Contagion®, and a clinical professor at Temple University of College of Pharmacy, said in a previous interview.

Just last week the CDC announced that experts in the influenza division of the agency have developed a portable flu laboratory that can sequence the influenza genome and analyze influenza A viruses in real-time and on-site in the event of an outbreak.

The kit, which is called Mia (Mobile Influenza Analysis), brings influenza sequencing into the field, which will cut the time needed to genetically analyze flu viruses in half and produce real-time actionable data that can be used in a public health response.

In an animal model study, a team was able to successfully use Mia to extract, sequence, and analyze flu samples in just 14.5 hours, a task that usually takes a week when samples must be sent to a laboratory for examination.

According to the CDC’s statement, the experts who developed the tool estimate that in the event of a flu pandemic, through proactive surveillance and using Mia, there would be an 8-week advantage for flu vaccine manufacturing.

Contagion® will continue to monitor influenza cases and the 2019-nCoV outbreak. To track the case counts in the COVID-19 outbreak, visit the Contagion® Outbreak Monitor.