What Do Coronavirus Vaccine Test Results Mean?
Big news: Moderna, one of the companies working on the coronavirus vaccine, released the results of a Phase I trial of its RNA vaccine this morning. At first glance, the news is exciting: the vaccine looks safe, and the antibodies are produced by volunteers.
But before we all start making our plans for what we will do after we all receive the vaccine, it is important to put these results in proper context. Here’s what you need to know.
Phase I testing is intended to test safety, not effectiveness.
As we wrote earlier, a Phase I trial primarily tests how safe a vaccine is , not how effective it is. In a phase I trial, healthy volunteers receive varying amounts of the vaccine and are monitored for any side effects. For this trial , 45 healthy volunteers were recruited and given different dose levels of the vaccine.
So far, the vaccine appears to be safe, and the FDA has cleared a Phase II trial , where volunteers at high risk of contracting the virus will be given a therapeutic dose.
Antibody data were obtained from eight volunteers.
In addition to testing the safety of various doses, the researchers also monitored volunteers for signs that the vaccine had stimulated an immune response by testing to see if they were generating antibodies against the virus. Moderna announced that of the 45 people in the study, eight were able to get tested and had expected neutralizing antibodies in their blood at levels “at or above” in people who recovered from COVID-19.
“This is great news,” says John Cook , a medical scientist at Houston Methodist Hospital who was not involved in the study, in an email to Lifehacker. “That being said, we still don’t know if the antibody response will protect people from disease.”
Proving that a vaccine is safe for eight people is very different from demonstrating that a vaccine is safe for millions of people. It also raises the question of how effective this vaccine will be: right now, researchers are studying whether it stimulates an immune response by creating antibodies similar to those found in recovered patients. While this is a promising result, there are several limitations.
Generation of antibodies is not necessarily a sign of effectiveness
According to Peter Hotez, a renowned vaccine scientist and expert in tropical diseases, indicates having antibodies against the virus is not necessarily sufficient.
As we wrote earlier, just because we can find antibodies against a virus in a patient does not necessarily mean that they were antibodies that were effective against the virus, so there is still a lot of work to be done to demonstrate how safe and effective it actually is. this vaccine. It is also problematic that these results were published by Moderna itself and not in a peer-reviewed study or preprint.
Conflicts of interest are also worth mentioning: one of Moderna’s directors, Moncef Sloughi, left the board of directors and became the chief research officer of the White House initiative to accelerate vaccine development. Sloughie currently has over $ 10 million in Moderna stock options. Since the news was released this morning, his share price has jumped about 25%.
This preliminary evidence is still good news.
Caveats aside, the fact that preliminary data show this vaccine looks safe and can boost the immune system is a good sign. It is also worth noting that this candidate vaccine has received FDA clearance to begin Phase II trials, with Phase III trials estimated to begin in July if Phase II trials continue to demonstrate its safety.
“Phase II testing will be more informative about the efficiency signal,” says Cook.
There are many more steps to be taken and many unknowns to take into account before we announce that we have found a cure, and any of them can show us that this particular vaccine is not the answer we are looking for.
Developing a safe and effective vaccine is, in many ways, a numbers game. One particular vaccine candidate may or may not be safe and effective, but may be different if not. So, while these early results are promising if this candidate fails the test, there is every reason to hope that one of the many others in development will turn out to be correct.
All in order to say: we do not yet recommend strengthening your plans for the post-quarantine period, but since this morning our hope for an effective vaccine has become a little brighter.