WASHINGTON — You better not cough. You better not sneeze. Cover your mouth. We’re begging you — Please! Flu virus is coming to town.
Cases of flu are starting to pop up all over Washington, and experts are warning that the new flu season could be at least as bad as last year’s nasty flu season, which killed 278 people in the state.
Each year, researchers try to predict which strains will be most common, and make a vaccine that combats those strains. Most years, their gamble pays off. But this year, there are signs that the vaccine may not be a good match for the dominant strain.
To get a sense of what the U.S. flu season might be like, researchers look to Australia, where flu outbreaks typically strike in July, August and September. This year, the Land Down Under experienced its highest number of flu cases since a pandemic broke out in 2009, according to the Australian National Notifiable Diseases Surveillance System. More than twice as many Australians were hospitalized for flu, and the period of peak flu activity lasted somewhat longer than in the previous year. There was also a corresponding spike in hospitalizations and deaths.
According to a report from Australia’s federal Department of Health, “The impacts of the season included high levels of absenteeism and a substantial burden on primary care and hospitals.”
Vaccine developers predicted a strain known as Flu A(H3N2) would be the most common form of flu, and designed the vaccine with that in mind. However, predicting what flu season will be like is notoriously difficult, because individual strains of flu virus can change significantly during the course of a single season. The H3N2 virus appears to have mutated at some point after the vaccine was created, and the vaccine was not a good match for the mutated virus. In Australia, it was only about 10 percent effective against H3N2.
In a September New England Journal of Medicine editorial, several doctors warned that the U.S. could be in “for a potentially severe flu season.”
The flu is just starting to gain momentum in the Northwest, so researchers don’t know yet whether the same mutated strain will dominate here. However, the U.S. flu season does tend to mimic the Australian flu season, according to the federal Centers for Disease Control. Our vaccine is the same one that was used in Australia, so if the changed H3N2 dominates here, its efficacy could be similarly low.
In their annual Flu Season Summary report, Australian health officials said this year’s flu didn’t necessarily cause more severe symptoms than in other recent years, but H3N2 seemed to be especially hard on seniors. A second type of flu, known as Influenza B, or “Yamagata,” was less common, but tended to sicken children.
As in most years, the Northwest’s flu season is kicking off just in time for Christmas. According to the Washington Department of Health, the number of cases began rising in the second week of December. There were 10 confirmed flu-related deaths between Oct. 1 and Dec. 16, compared to nine during the same period in 2016. So far, there have been at least 13 outbreaks in long-term care facilities.
In each of the last few years, the number of flu cases started rising dramatically in mid-December, peaked during January and then dropped back down to baseline levels in March or April.
So far this year, most of the cases have been caused by H3N2, but there has also been a small, but significant number of cases of Yamagata. Not all cases of suspected flu are treated, and doctors don’t always send samples to a lab for identification, so researchers can’t say precisely how many cases of each strain have showed up this year.
Because the flu shot was not especially effective in Australia, it might be tempting to skip it this year. State health officials say it’s still important to get vaccinated as soon as possible. Some people who get flu shots will still get the flu, especially in years when the vaccine is not a good match. However, vaccinated people tend to have milder symptoms, and recover more quickly.
Another good reason to get the shot, according to the state Department of Health, is that it will help prevent the illness from spreading to people who are especially vulnerable, like pregnant women, babies, people with compromised immune systems, and seniors.
“People who are sick should stay home from holiday gatherings where influenza and other illness can spread. If you have symptoms of the flu, it’s better to miss some of the holiday fun than to risk infecting others – especially those people who are at higher risk of serious complications,” State Epidemiologist Dr. Scott Lindquist said in a press release.
Doctors can prescribe antiviral drugs to treat the flu, but they work best if the patient starts them within the first 48 hours of becoming sick.
Most people with the flu can safely be treated at home, but there are a few symptoms that should trigger an immediate trip to the emergency room, according to DOH. These include shortness of breath or difficulty breathing, severe or persistent vomiting, seizures, confusion and sudden dizziness. It is especially important to watch for signs of dehydration in children, such as crying without tears, fewer wet diapers than usual, and not drinking enough fluids.