Updated: Mar 31, 2020
Doctors Urge Americans to Get Flu Shots Amid Fears Over Deadly Flu Strain. Should Singaporeans do the same?
The Wall Street Journal
By Sumathi Reddy
17 October 2019
California has already seen several flu-related deaths. ‘It does make me a little bit more nervous’ about flu season, one expert says.
Excerpt140/140Excerpt140/140Excerpt140/140Excerpt140/140Excerpt140/140Doctors are urging Americans to get their flu shots right away after a bad flu season in Australia has raised concerns about the coming season in the U.S.
Public health experts often look to the Southern Hemisphere's influenza patterns for clues of what's to come. This year Australia saw an earlier-than-usual peak of flu cases and had a tough season overall. The predominant flu strain in Australia, as in recent years in the U.S., was the H3N2 virus, which generally causes more severe illness, particularly among the elderly, and more hospitalizations and deaths.
"It does lead you to believe that this H3N2 virus is definitely on the move and is changing, which is never a good situation," says pediatrician Randy Bergen, clinical lead for the Kaiser Permanente flu vaccine program in Northern California. "It does make me a little bit more nervous than I am in general looking ahead to the flu season."
He says so far weekly surveillance data still shows relatively small numbers of flu cases but there have already been several flu-related deaths in California, which is a concern.
The Australian flu season doesn't always predict the U.S. one. Last year, Australia had a mild flu season with several different influenza viruses circulating, whereas the U.S. had a very long season with a new H3N2 variant emerging, says Dan Jernigan, head of the influenza division at the Centers for Disease Control and Prevention.
The World Health Organization has added that new H3N2 variant into the vaccine used right now in the U.S. Creating the flu vaccine is an imprecise science because it's hard to know exactly which strains will circulate in the coming season, and the virus can mutate quickly.
But experts say that even if the flu vaccine doesn't exactly match the strains that circulate, it's still far better to get a flu shot than to skip it. It provides protection for various strains that often circulate together, and there's evidence that the vaccine lessens the duration and severity of the illness even if you do end up getting sick.
Most importantly, even an imperfect vaccine helps prevent the spread to others, including infants 6 months and under who can't get a flu shot. The most common side effects from the shot are soreness and tenderness or swelling at the site of injection, though muscle aches, headache, and low-grade fever can also occur. More serious side effects are very rare.
"For many people, even if it's not perfect, it will probably give them some protection or modify the course of the disease if they become infected," says Stephen Morse, a professor of epidemiology at Columbia University's Mailman School of Public Health.
The CDC recommends that everyone over 6 months old be vaccinated by the end of this month. It takes about two weeks to be protected by the vaccine and protection usually lasts up to a year in healthy adults, though it can wear off more quickly for the elderly.
For the 2018-19 flu season, only about 45% of adults and about 63% of children got vaccinated. The CDC estimates that between 36,000 and 61,000 people in the U.S. died from the flu.
Two recent studies presented earlier this month at IDWeek, an annual meeting of infectious-disease specialists, found that getting the flu vaccine reduced the severity of illness in adults by more than one-third and cut hospitalizations of children by half.
In one study, CDC researchers analyzed data from more than 40,000 patients hospitalized with influenza over the course of five flu seasons. They found that patients between 18- and 64-years-old who came down with the H1N1 strain of the flu despite getting vaccinated had a 36% lower risk of dying, a 34% lower risk of mechanical ventilation and a 19% lower risk of ICU admission than patients who didn't receive the vaccine.
Patients 65 and older who tested positive for the H1N1 flu strain despite vaccination had a nearly one-third less chance of ICU admission than those who didn't get the flu vaccine. There was no statistically significant difference in outcomes for patients with the H3N2 or B strains.
"Even though people who get vaccinated can still get sick there are a lot of benefits of vaccination," says Shikha Garg, a CDC epidemiologist and lead researcher on the study.
In a separate study CDC researchers analyzed the hospitalizations of 3,630 children hospitalized for respiratory illness over two flu seasons.
Those who were vaccinated were half as likely to be hospitalized than those who weren't, says Angela Campbell, a medical officer at the CDC and lead author of the study. Protection was highest for the H1N1 version of the virus, with children who had a flu vaccine 76% less likely to be hospitalized compared with those who didn't receive a vaccine. Those who tested positive for a different strain -- the B influenza virus -- and had a flu vaccine were 59% less likely to be hospitalized, whereas those who had the H3N2 virus were 33% less likely.