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People wait in line at a COVID-19 vaccination clinic in the Los Angeles area. MediaNews Group/Long Beach Press-Telegram via Getty Images
  • Experts say there are a number of reasons flu shots are more readily available than COVID-19 vaccines.
  • For starters, there are currently more manufacturers of flu shots than COVID-19 vaccines.
  • There’s also an established structure for distributing flu shots while the COVID-19 vaccination system is still being established.
  • In addition, the Pfizer vaccine needs to be stored at ultra-low temperatures that limits where it can be delivered.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 pandemic.

So far this flu season, more than 193 million flu shots have been distributed across the United States.

Meanwhile, more than 69 million doses of the COVID-19 vaccine have now been distributed, according to the Centers for Disease Control and Prevention (CDC).

Why the disparity?

Experts say it’s not as easy as it may seem to vaccinate people against a new virus on this scale.

“One would have thought we in the U.S. could have delivered the vaccine in an efficient and effective manner. But for reasons that are beyond me, that was a more difficult task than had been anticipated,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University in Tennessee, told Healthline.

“Evidently it was much more elaborate and difficult than many of us had anticipated,” he said. “There were bumps in the road that predicted deliveries of vaccine didn’t always occur at the local level, and when vaccine arrived it was in smaller amounts than had been anticipated.”

Experts say it’s simply not as easy to roll out a new vaccine in the same way it is to distribute an annual influenza vaccine, which — due to years of planning and implementation — runs smoothly and on schedule.

“We’ve been making flu vaccines for many, many years. So all of the manufacturers have production systems and they know their targets. They each know how much vaccine they’re going to make. This is an ongoing, well-established, well-oiled machine that has been going on for many, many years,” Dr. Yvonne Maldonado, a professor of global health and infectious diseases at Stanford University in California, told Healthline.

“Whereas making a COVID vaccine… is a brand new enterprise and it requires ramping up rapidly, and carefully and safely, very, very large production plants and facilities that need to meet very strict safety and cleanliness and other criteria,” she said. “That doesn’t happen overnight. That takes time.”

Part of the reason influenza vaccines are so plentiful compared with COVID-19 vaccinations is simple numbers.

Currently, there are more companies making the flu shot than the COVID-19 vaccine.

“There currently are six manufacturers of flu vaccine as compared to the currently available two COVID-19 vaccines in the U.S. There are four additional COVID-19 vaccines in various stages of clinical trials with a possible high probability of reaching the market via FDA [Food and Drug Administration] approvals,” Krist Azizian, PharmD, MHA, the chief pharmacy officer for Keck Medicine at the University of Southern California, told Healthline.

As of Feb. 12, the total number of COVID-19 vaccination doses distributed was more than 69 million while the number of doses that had been administered was more than 46 million.

Part of the reasoning behind the lag in actual shots given comes down to logistics.

“Gaps in doses distributed versus administered have to do with the operational challenges and the availability of qualified clinical personnel to be able to vaccinate in large quantities,” Azizian said.

“The initial approach for distribution was directly to acute care facilities and designated vaccination megasites,” Azizian said. “What we will hopefully see soon is mass distribution and administration of vaccines leveraging the large chain retail pharmacies along with hospitals and mega vaccine sites, which will help expedite shots in arms.”

It’s not yet known how many people will need to be vaccinated to achieve herd immunity, but Dr. Anthony Fauci has said it could be in the range of 75 to 90 percent. Fauci is the the chief medical adviser on COVID-19 for President Joe Biden.

Such an undertaking, experts say, has never been attempted.

“We’ve never in the history of mankind done that,” Maldonado said.

It’s also the first time mRNA vaccine technology has been approved for use.

“The two currently available COVID-19 vaccines are manufactured based on new mRNA technology and are the first of their kind in this mode of delivery,” Azizian said.

That is adding its own set of challenges.

“Storage and transport requirements for the vaccines, administering two doses, and stringent reporting requirements at the state and federal level as a result of their approval under emergency use authorization pose significant challenges,” he added.

The Pfizer-BioNTech vaccine has cold storage requirements that limit distribution options.

“The ultracold storage requirements for the Pfizer-BioNTech vaccine makes it more difficult to mass distribute,” Azizian said. “The receiving location must have appropriate ultralow storage capability, which limits distribution to hospitals and larger healthcare organizations, rather than your local physician offices.”

Schaffner said the rollout of the COVID-19 vaccine is improving as the days go on.

“Clearly we’re getting better now at delivering the vaccine in a predictable fashion. We’re stumbling ahead faster than we were,” he said.

“The anticipation is we ought to be able to do this at least for the adult population by the end of the summer and then the hope is by the end of the summer we can start vaccinating children,” Schaffner said. “That will take a little bit longer. The projections suggest there would be enough vaccine so we could immunize 80 percent or more of the U.S. adult population.”

Schaffner noted: “Whether we’re successful will depend not only on the supply of the vaccine but on whether people will come forward for their vaccinations.”

With new strains of the virus posing new challenges, Schaffner said rolling out the vaccine is only the beginning of a long road ahead.

“Manufacturers are already not only planning but starting to create vaccines that are more specific to those variants, particularly the South African one. It may well be that down the road we’ll have to give people boosters at some interval,” he said.

“It’s conceivable since this virus is not going away, it’s not going to disappear… in the fall of a year you’ll have to roll up the sleeves of both arms and get the influenza vaccine in one and the COVID vaccine in the other,” Schaffner said. “As the circumstances evolve and the virus changes, our vaccination strategy will also have to evolve and change.”