(Bloomberg Opinion) -- Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answered questions about Covid-19 vaccine development and the path ahead in the pandemic fight after the U.S. Food and Drug Administration authorized Johnson & Johnson’s shot for emergency use.
J&J's vaccine is the first true one-shot dose to win clearance, and one that’s also easy to store and transport. It’s a good time to take stock of the vaccine landscape. So where are we?
J&J’s vaccine was the third in the U.S. to be authorized for use after the Pfizer Inc.-BioNTech SE and Moderna Inc. shots. The U.K. and European Union have also cleared three so far: the Pfizer-BioNTech and Moderna shots and one developed by AstraZeneca Plc and the University of Oxford. Globally, seven vaccines are being deployed. They’ve all generally been shown to be effective in combating Covid-19, with those made by Pfizer-BioNTech and Moderna having the best efficacy against all severity levels of the disease. Most vaccines also work well in preventing severe and critical cases, hospitalizations and deaths. That’s the main objective of the initial vaccination campaigns around the world – to downgrade Covid-19 to a less serious disease. We are now waiting for phase III data for AstraZeneca’s vaccine trials in the U.S. and for Novavax Inc. to update its phase III trial report with full data following encouraging interim data.
What have we learned so far as vaccines have rolled out?
We know from real-world data emerging from Israel, the U.K. and the U.S. that the effectiveness in preventing disease, hospitalizations and death is at least as good as the vaccines’ phase III trials had suggested, especially when there are no virus “variants of concern” to deal with. We have also learned that they are all safe so far, with even some of the safety signals that were potentially concerning during the phase III trials, such as the occurrence of Bell’s Palsy, not showing up in real-world safety analyses.
Are some better than others?
Yes. While none of the vaccines have been tested against one another in a scientifically sound trial, the data to date suggest that Pfizer-BioNTech’s and Moderna’s vaccines — which use new technology involving messenger RNA — have the best efficacy. Novavax looks set to potentially join them in the top tier. The data for AstraZeneca and Johnson & Johnson’s shots, which use technology similar to each other, look less impressive from the perspective of preventing mild-to-moderate disease. But they both appear effective in preventing more severe disease, which again is the chief objective, even if they are still not potentially as good as the Pfizer-BioNTech and Moderna shots.
What do we still need to know?
A lot. Durability of protection is key. All the data so far show that the vaccines are highly effective in preventing disease soon after inoculation. What we need to find out is what happens in six months or a year after vaccinations. Are they still as effective, or do we need boosters, even without viral variants causing an issue? There is also a lot of talk about the potential to reduce viral transmission, but I am worried we are jumping the gun a bit. We have to bear in mind that early on after vaccination, people have very high levels of antibodies, which help reduce the ability of the virus to take hold in the respiratory tract. As this high level of antibodies declines, the rates of mild disease may start to rise again along with an increased risk of transmission. This can be a problem, particularly for the AstraZeneca and J&J vaccines, with the latter actually showing less efficacy against milder disease even a few weeks after the dose. This means further waves of Covid-19 outbreaks are likely, though hopefully these will be mostly mild to moderate.
What about variants? We've already seen how some variants respond to vaccines; is it fair to say that in general the shots seem to work well enough against the ones that have cropped up so far? If variants do evade vaccines, what would that look like and how would we know?
I wouldn’t say that we know existing vaccines work well against variants. We need much more data. We know that at least the J&J vaccine had more than 82% efficacy in reducing severe-to-critical disease caused by the B.1.351 virus variant first found in South Africa. We don’t know how well any of them work against the P.1 variant first found in Brazil, or the newer versions of the B.1.1.7 variant in the U.K. and any of the potential variants found in the U.S. We also don’t know how the efficacy regarding the B.1.351 variant will shape up over time, though the data from J&J’s phase III trial was very promising with no new cases recorded 48 days after the dose out to four months. But what happens later? We don’t know. Also, the efficacy against mild-to-moderate disease was much less, and cases continued to be recorded over the four-month analysis period, while the data for the latter parts of the analysis is less mature and may get worse. As I noted above, this means viral transmission may continue.
Are drug companies working on vaccines to target variants?
Yes, all of them are doing this. And that is a critical piece of data that we still need to see: Do the new variant vaccines induce as strong an immune response against the new variants as existing shots do against the older versions of the virus? We also don’t know if giving a variant vaccine will protect people against the original form or whether we need a combined vaccine, which some companies are working on. We need all this data before we can get too comfortable with the idea that we can beat the virus at every turn that it takes.
How do vaccines work in people who have had Covid? Specifically, does vaccinating patients who have long Covid help them?
Those who have had Covid seem to respond very well to the vaccine, almost as if the vaccine is a booster shot. What is good to see is that we have yet to hear of vaccine-dependent disease enhancement – when a shot worsens illness — which is something to keep a close eye on. Also, there are anecdotal reports of those suffering from long Covid improving after vaccination. But this needs to be proved in trials and field studies. It’s possible that the effect is short-lived. On the other hand, it could indicate that there is a reservoir of virus in the body that vaccination helps eradicate.
What can people who have had bad allergic reactions to vaccines do?
Well, there have been very few reports of allergic reactions in surveillance data from the U.S. Centers for Disease Control and Prevention. People who know they have an allergy to a specific ingredient of the Pfizer-BioNTech or Moderna vaccines, such a polyethylene glycol, can now take the J&J or AstraZeneca vaccines, which don’t contain this. In fact, the CDC’s Advisory Committee on Immunization Practices said Monday that people who experienced an allergic reaction to one of the mRNA shots could take the J&J vaccine as a second dose. Those who have hypersensitivity reactions to all the vaccines, which is likely to be very rare, may gain some protection from treatments such as the monoclonal antibodies from Eli Lilly & Co. and Regeneron Pharmaceuticals Inc. and Roche Holding AG, or those being developed by AstraZeneca and GlaxoSmithKline Plc with Vir Biotechnology Inc., if shown to be effective.
What about children? So far only teenagers and adults have been inoculated.
Children can be infected with the Sars-Cov-2 virus and can have serious disease. But the rates are much lower. They are biologically less likely to be infected and have a very strong early immune response (innate immunity), which limits the virus’s ability to take hold. So it’s understandable that they haven’t been prioritized in the vaccination effort so far.
What will it take in the vaccination effort to be able to loosen restrictions that require social distancing and wearing masks?
This all depends on answers to several of the questions above: How long does immunity last? How well do the vaccines reduce or prevent transmission? Do variants evolve that can avoid the vaccines’ effect on mild-to-moderate disease? How much of this kind of disease and the inevitable severe cases are we going to tolerate? At the end of the day, I think we will get to a point where each government will need to decide what level of disease outbreak and severity it is going to accept. Flu can be a good way of thinking about this. There were about 600,000 global deaths from flu each year until the masking and social distancing of 2020 brought that figure down to a relative handful. What kind of mortality rate will we deem acceptable when it comes to Covid-19, given that it’s a more transmissible disease compared with the flu?
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
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