The coronavirus vaccine from Pfizer and BioNTech seems to be more effective than thought, without producing any serious safety concerns. However, the interim analysis comes from just 94 out of over 43,000 enrolled participants.

Record-breaking speed

An announcement by the two companies notes that the mRNA vaccine candidate seems to prevent 90% of COVID-19 cases after the second dose of vaccine. Officials were thrilled.

“The first interim analysis of our global Phase 3 study provides evidence that a vaccine may effectively prevent COVID-19. This is a victory for innovation, science and a global collaborative effort,” said Prof. Ugur Sahin, BioNTech co-founder and CEO. “When we embarked on this journey 10 months ago this is what we aspired to achieve.”

This is the first vaccine to be tested in the United States to generate late-stage data (although it is also being tested outside the US). Currently, 43,538 volunteers are enrolled in the study, with 38,955 of them having already received their second dose. Globally, 42% of study participants have racially and ethnically diverse backgrounds.

For months, researchers have warned that a Pfizer vaccine may only be effective in 60-70% of the cases. But if the interim data stands up, the results are much better.

“Today is a great day for science and humanity. The first set of results from our Phase 3 COVID-19 vaccine trial provides the initial evidence of our vaccine’s ability to prevent COVID-19,” said Dr. Albert Bourla, Pfizer Chairman and CEO.

The two companies will wait until they gather 2 months of safety data, as per FDA recommendations, and only then will ask for emergency regulation. No major side effects were observed so far although aches and fevers have been reported in some cases.

“We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks,” Bourla added.

But while this is important news and could mark a turning point in our fight against the pandemic, it’s important to also note some caveats.

Sparse details

For starters, this is just interim data: out of over 43,000 participants, this data only covers 94 — it’s not uncommon for interim data to be confirmed by the whole group, but it’s also not uncommon for results to change. Furthermore, the data have not been released for analysis and have not been peer-reviewed by external experts, only by company scientists. So overall, we don’t have that many details about the vaccine candidate.

Even if results are confirmed, which would be what officials are hoping for, there will be major distribution problems. The vaccine needs to be stored at ultra-cold temperatures, which makes delivery and storage very difficult. Pfizer is confident that the challenges can be overcome and expects 50 million doses to be delivered by the end of 2020, with another 1.3 billion by the end of 2021.

There’s also no way to tell for sure how long the vaccine will protect against infection since the study itself has only been running for a few months. Previous studies, however, suggest that it could last for months before waning, although revaccination will probably be needed in time.

We will need to see the full data and evaluate it independently, yet overall, the results seem to bode well — not just for Pfizer, but for other companies working on late-stage vaccines.

This announcement comes right on the back of another one by British-Swedish company AstraZeneca, which said they can have a working vaccine by the end of the year, if regulatory bodies move fast. Moderna, another company working on an mRNA vaccine should also be pretty happy to hear the news.

Having a working vaccine developed in less than a year is even better than the optimistic prognoses laid down when the pandemic started. The stakes have never been higher, and research companies seem to be delivering on their promise.

“There’s a lot at stake for humanity,” Dr. Bourla said. “If we get it right, the world can be saved.”