The current flu season is "still on the rise," the acting director of the US Centers for Disease Control and Prevention said Friday.
"We may be on track to break some recent records," Dr. Anne Schuchat added while releasing the latest data.
Flu-related hospitalizations rose to about 60 people out of every 100,000 in the fifth week of 2018, the CDC said Friday in its weekly surveillance report.
That's higher than last week, when the rate was 51 per every 100,000, and higher than during the fifth week of the 2014-15 season, which recorded about 44 people hospitalized per 100,000. The CDC considers the 2014-15 season "moderately severe" with high levels of illness, hospitalizations and deaths compared with previous seasons and has used it as a comparison to the current season.
Hospitalizations in the 55- to 64-year-old age group and higher levels of influenza-like illness are where the records will be, Schuchat noted.
"We don't have signs of hospitalizations leveling off yet," she said, adding that during a past severe season that looked similar to this one, an estimated "34 million Americans got sick with the flu."
In addition, 10 more flu-related deaths were reported in children as of the week ending February 3, bringing the total number of children who have died of flu-related causes to 63 for the season, which began in October.
Though cases along the northern border near Canada and a bit along the West Coast show some signs of easing, there are "likely many more weeks to go," CDC spokeswoman Kristen Nordlund said.
Caused by viruses, flu is a contagious respiratory illness with mild to severe symptoms that can sometimes lead to death. Circulating flu strains this season are a mix of H3N2, H1N1 and B viruses. Nordlund said. Anytime H3N2 strains are dominant, as they are now, "we tend to see more severe disease more hospitalizations, more deaths."
"There might be a second wave of influenza B infections," she said. "It's a little too early to say we're out of the woods or to say that flu is abating."
"It's not uncommon for B strains to increase later in the season," Schuchat said. During an intense season like this one, it is possible to get an infection with both A-strain viruses and B-strain viruses at the same time, and people definitely get sick twice from the flu, with first one strain and then another, she said.
According to the report, influenza activity was widespread in 48 states and Puerto Rico for the week ending February 3, the same as last week. Oregon and Hawaii, the exceptions, both recorded regional activity for the fifth week of the year.
The CDC also recorded a rise in the percentage of patients who visited health care providers complaining of influenza-like illness across the nation: 7.7% of patients for the week ending February 3, up from an estimated 7.1% during the previous week.
Levels of illness, based on outpatient visits and visits to emergency rooms, are "now as high as we observed at the peak of the 2009 H1N1 pandemic season," Schuchat said.
Although the current rates do not mean we're having a pandemic, she said, this is "a signal of how very intense this season has been."
Overall, the data showed 14,094 new laboratory-confirmed cases of illness during the week ending February 3, bringing the season total to 151,983. These numbers do not include all the people who have had the flu, as many do not see a doctor when sick.
Among adults, the proportion of pneumonia- and influenza-related deaths climbed to 10.1% of all deaths reported during the week ending January 20 (these data are always two weeks delayed). This rate is higher than the anticipated 7.3% pneumonia- or flu-related deaths estimated for the week.
It would make sense to see "a lot" of influenza deaths in the coming weeks, Schuchat said, based on the fact that many people are in the hospital. We need to "keep being vigilant," she said.
It's still "worthwhile" for unvaccinated people to get a flu shot, she said.
Even though the flu vaccine has low effectiveness against H3N2 viruses, it is more effective against other flu viruses, Schuchat said. Based on a recent Canadian report, the effectiveness against B strain viruses is estimated to be about 55%. The vaccine may also reduce the severity of symptoms if you catch the flu despite getting vaccinated.
The supply of the antiviral drugs used to treat patients with the flu exceeds the demand, although prescriptions are higher than in previous years, Schuchat said. The CDC is working with pharmacies, drug producers and others to better distribute the medicines and alleviate spot shortages.
She recommended calling ahead to pharmacies to make sure a prescription can be filled.
"The commercial supply is there," she said so dipping into the strategic national stockpile is not necessary.