Now Reading
What to know about Arizona’s COVID-19 vaccines (so far)

Note: This story is more than 2 years old.

What to know about Arizona’s COVID-19 vaccines (so far)

  • Those who are eligible to get a vaccine can call the state COVID hotline at 1-844-542-8201 or visit to find a location to get a vaccine.
    PixabayThose who are eligible to get a vaccine can call the state COVID hotline at 1-844-542-8201 or visit to find a location to get a vaccine.

More than 1 million Arizonans have gotten at least one dose of the COVID-19 vaccine, but unlike other immunizations, there are different vaccines that are being offered, leaving many to wonder: What differences are there between the available vaccines and does it matter which one I get?

Public health officials across the nation and Arizona have a simple answer: The first one a person should get is the best vaccine.

“Whatever vaccine is available to you and whenever you can get an appointment please do it,” said Dr. Rebecca Sunenshine, the medical director for disease control at the Maricopa County Health Department. “Please get the one you have available.”

There are currently three main COVID vaccines being used around the world, with a fourth expected to receive approval soon, but only two are being used in Arizona at the moment.

Vaccines made by both Moderna and Pfizer are currently available in Arizona, and each requires two doses, administered roughly a month apart. But the one-dose vaccine developed by Johnson & Johnson, which is still awaiting federal approval, will be coming to Arizona “in a couple of weeks,” Sunenshine said.

The novelty of the vaccines, and their importance in combating the pandemic, have made the companies that produce them household names in a way that hasn’t happened before.

“It’s not something that is discussed in the public domain for the flu or any other vaccine product,” Richard J. Webby, PhD, an expert in influenza and a member of the Infectious Diseases Department at St. Jude Children’s Research Hospital and the World Health Organization’s Vaccine Composition Team said. “But this is a completely different ballgame, for sure.”

Despite all the different brand names and differences between the shots, Webby and public health officials are urging anyone who is able to get a vaccine to get the first one they can.

“ADHS has no preferred COVID-19 vaccine since both have been found to be safe and highly effective,” ADHS said in a statement to the Arizona Mirror. “We encourage everyone to get vaccinated against COVID-19 when they are eligible.”

COVID is already impacting how the everyday consumers vaccines are being manufactured and likely will have an impact on future vaccines as well.

Both the Pfizer and Moderna vaccine use fairly new techniques on how they deliver the information to our bodies to teach our immune systems how to fight off the novel coronavirus, which causes COVID-19.

What these vaccines have in common with other vaccines is that they still work by delivering a viral protein to our body’s cells, which triggers an immune response and thus trains our immune systems to effectively attack the virus, Webby said.

It’s the delivery method in each vaccine that sets each vaccine apart and is changing how we could do vaccines in the future.

Both the Moderna and Pfizer vaccines being administered in Arizona use mRNA to instruct cells to make a specific protein to trigger an immune response.

The technology is brand new, and differs from traditional vaccine development, in which crippled versions of a virus are created, often grown in chicken eggs, and then killed so the protein can be taken from those dead viruses and injected into people to trigger the immune system to copy the virus’ genetic material and develop an immunity.

The AstraZeneca vaccine, which is widely used in Europe, and the forthcoming Johnson & Johnson vaccine both use the traditional method.

The upside to those vaccines is that they can be delivered in one shot, and they are far more durable and have a longer shelf-life. By comparison, the Moderna and Pfizer vaccines require two doses and must be kept at extremely cold temperatures before they start to degrade.

A shot from Moderna requires a 4 week waiting time between doses while Pfizer requires 3 weeks between doses.

Moderna and Pfizer may have similar delivery mechanisms but the way they are stored is quite different. Both have to be stored in cold temperatures, but the Pfizer vaccine has to be stored at minus-94 degrees Fahrenheit compared to Moderna’s minus-4.

“This is not your regular freezer,” Webby said, about how the vaccines have to be kept. The AstraZeneca vaccine can be kept in a normal refrigerator but is only available currently in Europe.

The AstraZeneca vaccine also varies from the Moderna and Pfizer vaccines in how it delivers the protein needed for the body to trigger an immune response. The vaccine uses a crippled version of a common cold virus as a carrier to get the protein into our cells, this method is a bit more “traditional,” Webby said.

The Johnson & Johnson vaccine also uses this method to deliver its dose.

Webby said right now it is too early to tell which vaccine is going to likely be the most effective, but the limited research has shown that the vaccines have higher than normal effective rates and the methods being used by AstraZeneca, Johnson & Johnson, Moderna and Pfizer are working better than the direction being undertaken in China.

“It’s going to be much easier to translate these methods to some of our other vaccines like flu,” Webby said about the vaccines. Currently flu vaccines have a 50% to 60% effectiveness rating compared to the up to 90% effectiveness rating the COVID vaccines have been reporting.

“It isn’t like anything we’ve faced before,” Webby said of COVID, noting that the virus has completely changed how the medical industry creates vaccines, reiterating that anyone who can get a shot, should.

Those who are eligible to get a vaccine can call the state COVID hotline at 1-844-542-8201 or visit to find a location to get a vaccine.

This report was first published by the Arizona Mirror.

— 30 —

Top headlines

Best in Internet Exploder