Lottsa Vaccine Questions Answered


Q: How much longer until there’s a $#&^#% vaccine?!?!

Q: How do vaccine trials work, by the way?

Q: Once there’s a vaccine, the pandemic is over, right?

Q: How will I know if it’s safe to get the vaccine?

Q: What about that AstraZeneca trial that was stopped?

A: Lotsa vaccine questions! Answers below. (Thanks to those who submitted questions to our Question Box!)

Q: How much longer until there’s a vaccine?!?!

A: We just don’t know. There are 9 COVID-19 vaccines currently in Phase 3 trials, including 3 that have been enrolling subjects in the US: Moderna, Pfizer/BioNTech, and AstaZeneca/Oxford. The CDC has asked state public health agencies to make plans and be prepared to roll out a vaccine in “late October”; however, the co-chief of Operation Warp Speed Moncef Slaoui said recently that it was “possible but very unlikely” that a vaccine would be ready by then. So, best guess puts it sometime between late 2020 and the first half of 2021. (Link to vaccine trial tracker below).

Q: How do Phase 3 vaccine trials work, by the way?

A: In a Phase 3 trial, about 30,000 study subjects are enrolled and then randomized to get the experimental vaccine or a placebo. They may get multiple doses over a few weeks. Then, everyone waits. Phase 3 trials are “event-driven” trials, which means that the researchers can conduct a preliminary analysis once enough events happen — in this case, an event is a case of COVID-19. Once there are enough events, researchers compare the # of cases in subjects who got the vaccine to the # of cases in subjects who got the placebo. If most of the cases are in placebo subjects, that suggests the vaccine does a good job of protecting people from disease. (Link below for more details.)

Q: Once there’s a vaccine, the pandemic is over, right?

A: Sadly, no. Having one or more vaccines will definitely help us get back to normal, but it won’t happen overnight, for at least two reasons: The first is that there won’t be enough vaccine for everyone to get vaccinated right away. Many countries, including the US, are formulating “allocation plans” to determine who will be first in line (see link below). Front line health care workers and first responders with high exposure risk, and people with underlying conditions that make having COVID-19 particularly risky are typically high-priority populations. The second reason we can’t immediately return to business as usual even once we all get vaccinated is that the approved vaccine may only be about 50% effective. What does that even mean? It means that the vaccine has to be shown (in Phase 3 trials, see above) that it reduces the risk of getting COVID-19 by 50% compared to unvaccinated people. Because a 50% effective vaccine will reduce but not eliminate cases (it may also reduce the severity of cases, which is good), we still may be masking and doing at least some form of distancing and restricting social contact for a while.

Q: How will I know if it’s safe to get a vaccine?

A: Several factors have given rise to concerns about whether an approved vaccine will be safe: The first is the speed at which the vaccines are being developed — much much faster than any prior vaccine development timeline. The second is the perceived politicization of the approval process. In a recent survey, 78% of Americans said they were worried about the vaccine approval process being driven more by politics than by science. If there is the appearance or perception that the FDA (the federal agency responsible for vaccine approval) is cutting safety corners in order to rush a vaccine out before, say, the November election, people may not trust that the vaccine is safe.

To counter these concerns, both the FDA and the pharmaceutical companies have recently pledged (see links below) that the approval process will be rigorous, guided by science, and include independent oversight.

One thing to watch for: the FDA can choose to give an Emergency Use Authorization (EUA) for a vaccine before the longer Biologics License Application (BLA) approval process is completed. The FDA official responsible for vaccine approval suggested last week that guidance would be coming soon about an “EUA-plus” approval process, requiring more data than a typical EUA. This could very well be the approval mechanism for the earliest vaccines.

(See link below for Nerdy Girl chat with Dr. Malia Jones and Dr. LIndsey Leininger for more on vaccine safety perceptions and reality.)

Q: What about that AstraZeneca trial that was stopped?

A: Last week the news broke that the AstraZeneca/Oxford Phase 3 vaccine trial had been paused after a subject in the UK developed a “severe illness”. While AstraZeneca has not confirmed this, it is widely reported that the illness was transverse myelitis, a rare spinal cord inflammation. AstraZeneca reported that the pause was being triggered by “standard review procedures”, which some scientists noted was a good sign that all safety protocols were being strictly followed. The trial was restarted in the UK on September 12, but as of Tuesday the FDA had not approved a restart in the US.

Stay tuned for more. The vaccine news is coming fast and furious these days, and we’ll take our best shot (ba dum bum) at keeping you up to date.

Links for more info:

NPR vaccine trial explainer

NYT vaccine tracker

FDA Pledge

Pharmaceutical company pledge

AstraZeneca trial pause

Nerdy Girl video on vaccine safety

National Academic of Science, Engineering and Medicine draft vaccine allocation framework (full disclosure: Nerdy Girl Dr. Alison Buttenheim is a member of the National Academies committee that developed this framework).

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