A powerful flu shot that provides extra protection for older people with weaker immune systems is becoming a hot commodity for health-minded seniors. But as a new flu season gets underway, it’s not always easy to find.
Some medical clinics and retail sites offering the Fluzone High-Dose vaccine, approved by the Food and Drug Administration for people over 65, have not yet received shipments they ordered from the manufacturer. The delays stem from the difficulty the World Health Organization encountered this year in identifying the changing strains in the 2019-2020 influenza virus.
That means seniors clamoring for high-dose shots, which have become increasingly popular since they were introduced nine years ago, are trekking from one drug store or doctor’s office to another. The vaccine contains the same three flu strains as the standard shot, but at four times the concentration of the antigen that boosts the immune system.
“They have signs all over the store saying ‘Come in and get the flu shot,’ and it’s not there,” said Joyce Westner, 73, of Winchester, who looked for the high-dose vaccine at two pharmacies and an urgent care clinic before tracking it down at a Rite Aid in Woburn. A pharmacist there told her they “just got a shipment and just have a few doses left,” she said.
Sharon resident Valerie White, 74, said the high-dose shot was unavailable at a drug store in her Canton supermarket, but she later found it at a CVS in Sharon. “I’ve never had the flu, so I can’t tell you whether it works or not,” she said. “But I wanted the heavy-duty shot.”
The sinking feeling upon learning the vaccine is out of stock is reminiscent of the shortages that accompanied the rollout of a new shingles vaccine, called Shingrix, to prevent the painful nerve inflammation and skin rashes of another virus that torments older adults.
But while that was caused by an inability of the supplier to ramp up production to meet demand, there is no shortage of the high-dose flu vaccine, according to its manufacturer, the French drug maker Sanofi Pasteur. The company said some doses are just being shipped later than in past years because of the WHO’s delay in determining this year’s formulation.
“Three-quarters of the vaccine supply has been shipped,” said Monica Mercer, medical director at Sanofi Pasteur’s manufacturing site in Swiftwater, Pa., who said the company has alerted customers to its shipment schedule. “We will continue to ship till November.”
Executives at Sanofi Pasteur couldn’t project the number of Fluzone High-Dose injections that will be administered in the United States this year. But they said the number has been climbing since the vaccine entered the US market in 2010. And it spiked, they said, after the company in 2014 released the results of a clinical study showing there were 24 percent fewer cases of flu among seniors who received the high-dose vaccine — and 6 percent fewer cases of those hospitalized for flu-related illnesses — than among seniors who took the standard flu shot.
Mercer said roughly two-thirds of older adults who get flu shots now get high-dose vaccines, citing a growing recognition that people’s immune systems weaken as they age.
“Seniors don’t mount as strong a response to the standard-dose flu vaccine as younger adults do,” Mercer said. “They’re more vulnerable to the severity of flu.”
Overall, the vaccine maker expects to deliver 70 million doses of all types of flu vaccines this season, including 25 million doses of higher-concentration vaccines. Those include not only Fluzone High-Dose but also a four-strain vaccine called Flublok Quadrivalent, approved by the FDA for adults over 18 but shown in clinical studies to be most effective for those over 50. The shipment delays also affected the four-strain vaccine at some locations.
Because the composition of the higher-dose strand is the same as that of the standard dose, doctors say, its side effects are similar — some patients experience short-term muscle pain in the arm that receives the shot, tiredness, dizziness, or headaches — but could be slightly more severe. Nonetheless, they believe that all seniors should be vaccinated against the flu.
“The basic message is you should get a flu shot,” said Dr. Brian Chow, infectious disease physician at Tufts Medical Center in Boston, which administers the high-dose shot to older patients. “And if you’re over 65 and the high-dose vaccine is available, it would be good to get it.”
But the Centers for Disease Control and Prevention, which also urges that everyone be vaccinated against influenza, has yet to preferentially recommend the high-dose vaccine over the standard flu shot for all seniors. That could change when the agency completes its own analysis of clinical data.
For now, the high-dose vaccine is seen as “more of a targeted approach for people 65 or over who might be more susceptible to the flu,” said CDC spokesman Scott Pauley.
That leaves it up to individuals and their doctors to decide whether they should line up — or scour their communities — for the high-dose shots. But an increasing number are opting to do so, believing they’re more likely to fend off the flu with the higher concentration.
“It’s a numbers game,” said Westner, the Winchester resident who’s been getting the Fluzone High-Dose vaccine for the past several years. “My husband refuses to get the flu shot. But I’m betting on myself, and he’s betting on his immunity.”