Why the Covid-19 vaccine is rarer than the flu vaccine

In short, there are fewer manufacturers and distributors of the Covid-19 vaccine. It must be frozen in ultracold temperatures, making transport and storage difficult. Complete immunization requires two vaccines, compared to one for influenza. And since the serum is new, healthcare professionals should allow more time to monitor patients for possible adverse reactions.

All of this must be documented to ensure that the scarce vaccine is not wasted; allergic reactions are captured; and the second doses, which must be administered within a certain time, are properly performed.

“The challenge is that state health departments need to exquisitely monitor the doses that go in the arms,” ​​said Litjen Tan, director of strategy for the Immunization Action Coalition, an organization that distributes information about vaccines in partnership with the Control and Prevention of diseases . “With the flu shot, you get it and go.”

Currently, only Pfizer and Moderna manufacture Covid-19 vaccines available in the US, although versions from other manufacturers, including Johnson & Johnson and AstraZeneca,

are planned.

In comparison, at least four large companies make flu vaccines, which are delivered directly to healthcare providers by three large distributors and several smaller distributors.

Only one distributor, McKesson Corp.

, supplies the Covid-19 vaccine from Moderna to the federal government. Since Pfizer’s vaccine is to be frozen in more extreme temperatures, the company packs it in special thermal senders and works directly with FedEx and United Parcel Service to transport it.

“There are advantages and disadvantages to having an exclusive distributor,” said Josh Michaud, associate director of global health policies at the Kaiser Family Foundation, a nonprofit organization focused on health issues. “It is easier for the government to work with a company. They are not juggling multiple contracts and touch points. “

When the distribution of the Covid-19 vaccine increases, there will be “a strong case” for expanding the number of distributors, he said. “McKesson is big, but is he able to reach every corner of every state? Others have relationships with doctors’ offices and medical establishments. “

Flu vaccine manufacturers are also ahead.

Since the mechanisms for producing and distributing the flu vaccine are well established, healthcare professionals can order vaccines in January or February, which will be administered in the fall and winter. Production starts six to nine months before distribution, which is then phased out over a period of about four months. This season’s distribution started in August.

In contrast, the first Covid-19 vaccine was authorized for emergency use by the Food and Drug Administration on December 11 and distribution began on December 14. States find out how much Covid-19 vaccine they will receive about a week in advance.

“It’s more of a just-in-time management strategy,” said Crystal Tubbs, associate director of pharmacy at Ohio State University’s Wexner Medical Center, which administers about 2,000 Covid-19 vaccines per day. “We are informed five to seven days in advance of the amount of vaccine we will receive the following week. So we plan the commitments. “

The flu vaccine can be refrigerated, while the Covid-19 vaccine must be stored at extremely low temperatures.

Moderna vials contain 10 doses of vaccine and must be frozen at minus 4 degrees Fahrenheit. Pfizer vials contain five or six doses and must be frozen at less than 94 degrees Fahrenheit.

“We are talking about brutal cold,” said Tan. “This does not mean that it cannot be done, but we have to go more slowly. We have to be more deliberate and considerate ”.

After the bottles are punctured, all doses must be used within six hours – or discarded.

After vaccination, the person should be monitored for 15 minutes or, if they have a history of allergic reaction, for 30 minutes, to ensure that they do not react badly.

Immunization is not complete until a second dose is administered, and the final injection should take 21 days for the Pfizer vaccine and 28 days for the Moderna product.

As the Covid-19 vaccine is being administered to a population without previous resistance to the deadly disease, the goal is to inoculate as many people as possible.

“With the flu vaccine, about 50%, or perhaps a little more, of the US population is vaccinated in one season,” said Dr. Michaud. “With the Covid vaccine, the ultimate goal is to achieve a level of vaccination for herd immunity. Nobody knows exactly what it is, but at least it is 70%. “

So far, the USA is nowhere near.

Of the 55.9 million doses of Covid-19 distributed as of Thursday, only 33.9 million have been administered, according to the CDC.

This includes 27.2 million people, or less than 10% of the population, who received at least one injection, and 6.4 million, or about 2%, who are fully immunized.

The agency also estimates that 83.1 million people, or about 25% of the country, have been infected with Covid-19, although it is unclear how long their immunity can last.

Meanwhile, enough flu vaccine has been distributed to inoculate more than 58% of the population and, according to the survey results, 53% of all adults have already received it.

Write to Jo Craven McGinty at [email protected]