By Dr. Mallika Marshall

BOSTON (CBS) – Pfizer and German drug manufacturer BioNTech had very positive news about their coronavirus vaccine Monday.

Pfizer said early data of almost 44,000 participants in a phase 3 clinical trial shows the vaccine is more than 90-percent effective in preventing COVID-19. And so far, there appears to be no serious safety concerns. The vaccine is given in two doses several weeks apart.

I’m definitely encouraged by these results. We were hoping to have a successful vaccine candidate or candidates by the end of the year and 90-percent efficacy is remarkable.

But, this is preliminary data and the effectiveness could change as the trial continues. It’s also not clear how long immunity might last. However, Pfizer seems confident and hopes to apply for Emergency Use Authorization by the FDA later this month.

Here are some questions to consider going forward:

How quickly could the vaccine be delivered to the public?

Pfizer expects to produce up to 50 million doses in 2020 and up to 1.3 billion in 2021. Keep in mind, each person would need two doses. And if the vaccine is deemed safe and effective by the FDA, it will presumably be rolled out in a stepwise fashion, ensuring the people at greatest risk, like frontline workers and the elderly, get vaccinated first. As for the public at large, we might see a vaccine in the spring of 2021.

There have been some concerns about how difficult it might be to roll this vaccine out to the public. For example, it has specific storage requirements.

The vaccine has to be kept at very cold temperatures, minus 94 degrees Fahrenheit, which would require special equipment for shipping and storage. But the company is reportedly working on making the vaccine more stable and has been working on plans for worldwide distribution.

Pfizer says their vaccine is at least 90-percent effective. Is that high compared to other vaccines?

Yes. First of all, the FDA had said a vaccine should be at least 50% effective to win approval. And some experts didn’t expect a first-generation vaccine to be more than 55-60% effective, so 90% far exceeds that. And for comparison, the flu vaccine typically is only about 40-60% effective each year. If Pfizer’s vaccine really is more than 90% effective, it would work more on par with one dose of the measles vaccine, which is about 93% effective.

A recent survey conducted by ClearPath Strategies found that only about 38% of U.S. respondents said they would be willing to get a vaccine within the first three months of approval and 29% said they would wait at least a year. That doesn’t bode well for universal vaccination.

Understandably, a lot of people are concerned that a vaccine is being rushed to market without a thorough review process or worried that politics will influence the timeline instead of science.

But the preliminary Pfizer data were analyzed by an independent committee of experts, not by the company itself, which should provide some assurance. And if the effectiveness of the Pfizer vaccine and others coming down the pike remains high, that could go a long way to convincing the public, including skeptics, that getting a COVID-19 vaccine is safe and worth it.

Dr. Mallika Marshall

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