How Many Different Covid-19 Vaccines Do We Need?


Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answered questions about Covid-19 vaccines. The shot developed by Pfizer Inc. and BioNTech SE was the first to win early use authorization, but there are a handful of other candidates in trials, and one by Moderna Inc. may get the green light for use in the U.S. as soon as this week. The vaccine effort has been heroic and speedy, but it’s hard to keep track of the myriad candidates, and their differences raise questions. The conversation has been edited and condensed.

Moderna’s Covid-19 vaccine is all but certain to gain authorization by the U.S Food and Drug Administration this week, and Pfizer-BioNTEch’s shot is already in use. If there are two approved vaccines, isn't that good enough? Why keep working on more?

SF: This is a very good question, especially now that we have two vaccines that are using new technology and working much better than we had hoped. But there are several reasons to keep going with other ones. First and foremost, we need a lot of doses. If we were to rely just on Pfizer-BioNTech and Moderna's vaccines, we would need to wait about six years to vaccinate the world's population, based on their current expected production capacity in 2021. Also, both of those vaccines need to be kept at ultra-cold temperatures in deep freezers. By contrast, the shots being developed by Johnson & Johnson and Novavax Inc. only require simple refrigeration. Lastly, we have no idea which vaccine is the most long-lasting. As an example, there are hints of a slightly lower efficacy with Moderna's vaccine in those older than 65 than with Pfizer-BioNTech. While this may be just pure chance, given the number of cases involved, it would be remiss to ignore it.

Do I have a choice in what vaccine I get? Are some better than others?

As noted above there are several ways vaccines can end up being different from one another, and only time will tell. What we know so far is that among the vaccines produced by Pfizer-BioNTech, Moderna and AstraZeneca Plc (working with the University of Oxford), the efficacy in reducing the incidence of severe Covid-19 disease is approaching 100%. That’s very good. So even though we may not have a choice in which vaccine we take, at least at the start, it is not important in the context of solving the pandemic. They all seem to work well. If some vaccinations wear off over time or require annual or biennial shots, then the differences between them will become more important.

With more details from two vaccines, what’s the latest on safety? Anything new to worry about?

So far the safety data look great, certainly for the Pfizer-BioNTech vaccine. But we will need longer-term use in a large population to know about any rare events. We already know that as with most vaccines, people who have severe allergies may need extra supervision because of the risk of side effects. There was a report this week of a health worker in Alaska who had an extreme allergic reaction to the Pfizer vaccine, though we need more details about why this happened. The FDA has also discovered a slight incidence of Bell's palsy resulting from the Moderna and Pfizer-BioNTech shots. But the rates of these occurrences are still within expectations for the size of the population tested. Nevertheless, while the cases have mostly resolved, the FDA will be asking for surveillance of patients.

On approvals, should I be worried if, say, Pfizer is cleared in the U.S. but still under review in the European Union?

Not if you're in the U.S. Many commentators reacted negatively to the U.K.'s fast approval of the Pfizer-BioNTech vaccine, and now they are questioning why the EU is so slow, on a relative basis. The reality is, we are talking about differences of days or at most a couple of weeks. The regulators are generally all on the same page. This is nothing in the grand scheme of things, though of course the faster an effective vaccine is approved, the quicker the opportunity to save lives. But I think regulators have done the best they can in getting vaccines to the masses. Now we have to deal with the reality of distribution and persuading people to get their jabs.

There are a lot of people to vaccinate in the U.S. The initial Pfizer-BioNTech shots are a start, but they don’t come close to covering the need. Are there enough doses?  

On paper, the U.S. has signed up for more vaccine doses than it needs for its whole population. The issue is that these deals were all done before we had any idea of the relative efficacy of the vaccines. The U.S. will have 300 million doses – 100 million from Pfizer-BioNTech and 200 million from Moderna – at its disposal through the first half of 2021. This is enough for 150 million people, or half the U.S. population, assuming no wastage, because each vaccine requires two shots. While this does not fit with the promise of getting most of the U.S. vaccinated by the middle of next year, it is probably much more realistic, given the massive logistical issues involved and the continuing hesitancy of some people. There will be other vaccine trial results coming out very soon too, and that may lead to more candidates being authorized for use. AstraZeneca’s and J&J's U.S. trials will be done early in the first quarter, while Novavax will have its large U.K. trial data in the same time frame.

When should we expect to see the effects of the vaccination efforts on people’s everyday lives? What would that look like?

It depends. If the goal primarily is to reduce hospitalizations and deaths, and not so much viral transmission – which these vaccines haven’t proved to do - then mass gatherings are possible by the third quarter of 2021. If we really want to knock the virus on its head, then we will likely need to still avoid those kinds of super-spreader events until 2022. All of this is highly dependent on the uptake of vaccines and the durability of protection. As citizens, we have control over the first. Sadly, only time will tell how good vaccines are long term. What is really important is to make sure that in their haste to reopen their economies, political leaders avoid two mistakes: not relying on herd immunity, as we still don't know who is really protected after a natural infection, and not relying on the 'vaccine-works-well-after-one-dose' idea. Patience is needed.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Sam Fazeli is senior pharmaceuticals analyst for Bloomberg Intelligence and director of research for EMEA.

©2020 Bloomberg L.P.

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