It’s a big time for coronavirus vaccines. Here in the U.S., we got our first emergency use authorization (EUA), for the Pfizer/BioNTech vaccine, just days ago on December 11. The same vaccine was rolled out in the UK and Canada a few days before that; and now the Moderna vaccine is scheduled for review by the FDA this week, with its EUA potentially coming by this weekend.
So it seemed like a good time to update our field guide of vaccines in the pipeline for potential approval in the U.S. Currently, there are four, including the one that received emergency authorization. (A fifth, Novovax, plans to start U.S. trials soon.) The vaccines that receive EUAs will continue their studies and will likely apply for full approval later—an EUA is essentially a temporary approval for use during an emergency.
Worldwide, the New York Times vaccine tracker currently counts 17 vaccines in phase 3 trials worldwide, with five in limited use and two fully approved. (Phase 3 is the last and largest round of testing before a vaccine is approved.)
The four vaccines being tested in the U.S. are all a bit different from one another: some require ultra cold storage; some require two doses instead of one; some are mRNA vaccines, a new technology. Here’s a rundown of which are which, and how they each work.
Pfizer/BioNTech
Type of vaccine: mRNA
Status: This was the first COVID vaccine to receive an emergency use authorization from the FDA. Results of the phase 3 trial were published in the New England Journal of Medicine and in an FDA memorandum. They showed that the vaccine was about 95% effective and that there were no serious safety concerns in two months of follow-up.
Storage: This vaccine requires ultra-cold storage, colder than typical freezers are able to provide. It is shipped in special coolers that can keep the vaccine at temperature for up to 10 days. Each cooler contains 975 doses of the vaccine.
Required doses: Two.
Moderna
Type of vaccine: mRNA
Status: Phase 3 trials have been completed, and an FDA panel will meet on December 17 to review the vaccine for potential emergency use authorization. Interim results showed 94.5% efficacy, and the full FDA briefing document is here, with more results.
Storage: It can stay at freezer temperature for six months and refrigerator temperature for one month.
Required doses: Two.
Fun fact: Dolly Parton contributed to a research fund that was involved in the vaccine’s development.
AstraZeneca/Oxford
Type of vaccine: It’s based on a chimpanzee cold virus that cannot reproduce in humans and has been modified to carry a protein from the coronavirus.
Status: The company recently published positive results from a combined phase 2 and 3 trial. Unfortunately, errors and problems in the trials may have affected the results, so it’s difficult to tell whether the positive results indicate the vaccine actually works.
Storage: Standard freezer temperature.
Required doses: Two.
Johnson & Johnson
Type of vaccine: It’s based on a human cold virus that has been modified not to replicate and to carry a protein from the coronavirus.
Status: This one is also in phase 3. Trials have recently resumed following a brief pause due to a participant’s illness.
Storage: Standard refrigerator temperature.
Required doses: One, although the company is also testing a two-dose regimen.
This post was published in November of 2020 and was updated on December 16, 2020 to reflect recent developments.