BioNTech and Pfizer’s COVID-19 vaccine is surprisingly effective, though experts wonder what its effectiveness will look like in the real world

The companies, which teamed up in March to develop a vaccine for the coronavirus, said in a press release Monday that an interim analysis from the Phase 3 clinical trial indicates that BNT162b2, their investigational mRNA vaccine, has a efficiency rate greater than 90%. The study protocol calls for an efficacy rate of 60%.

“Considering everything that the world is going through and being humble enough to admit that we are still learning a lot about this virus, it was always a relief to see,” Steve Seedhouse, analyst at Raymond James, wrote in an email.

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But clinical trials are also conducted in controlled clinical settings that are unlikely to be replicated in the real world.

“In the clinical trial, you select the patients you love and you follow them very closely,” said Mizuho Securities analyst Difei Yang. “In the real world, there are all kinds of ages and each has different underlying health issues.”

In studies like those conducted for COVID-19 vaccines, this could include anything from how a vaccine is stored and handled by medical professionals to the types of people who volunteer to participate in a study. clinic, who may be more likely to be socially distant and wear a mask, especially if it is not clear whether they received the experimental vaccine or the placebo.

“When you put [a vaccine] in the real world, people can behave differently, ”said Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital in Philadelphia. “They think, ‘Great. I’m fine. The vaccine works. It is 90% effective. I can take off my mask. ”

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Additionally, data shared by BioNTech and Pfizer was collected approximately two months after trial participants received the second and last dose of the candidate vaccine. There are still questions about the duration of immunity to the virus, whether through natural infection or vaccination, and different durations of durability could impact the effectiveness of a vaccine.

“As the vaccine is adopted into the real world, if the durability of efficacy decreases over the months, then you will start to see a reduction in that number by 90% over time,” wrote Seedhouse. “But even though we don’t know much about [the] Still, the general lack of widespread reinfection around a year after the onset of this pandemic suggests that the durability may be good enough to keep efficacy this high, even in the real world.

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There is still no detailed information on how the vaccine worked in different vulnerable patient populations, including the elderly and people with co-morbidities such as diabetes or hypertension that can make them more vulnerable to infections and more severe forms of the disease. (BioNTech and Pfizer have yet to publish the study in a peer-reviewed or pre-printed format, which would provide more detailed results from the late-stage trial, but have said they will.)

Knowing how the vaccine worked in the elderly or those with co-morbidities “will really tell us how good the vaccine is,” Yang said. “One of the prevailing expectations was that people weren’t sure we could get back to where we were, even with the vaccine.”

There are a handful of vaccines in advanced development in the United States, including one from Moderna Inc. MRNA,
+ 1.79%,
which is also developing an mRNA vaccine and is expected to publish data from its phase 3 clinical study soon.

So far this year, BioNTech shares are up 211.7% and Pfizer shares are down 1.7%. The S&P 500 SPX,
+ 1.36%
is up 9.5%.