Question: On March 6, vaccine researcher Geert Vanden Bossche published a section of a speech he gave on mass vaccination with mRNA vaccines, which he believes will assuredly lead to enhanced adaptive immune escape. Care to comment on his stance?

Answer: I noticed that this letter* was making a lot of waves on social media, so in the interest of quelling rumors and disinformation, I will comment.  My topline message is this: Immune escape is of concern, but the focus of Dr. Vanden Bossche’s concern on mass vaccination campaigns is misplaced.  Rather, the quick and effective roll out of vaccines, including mRNA vaccines, will limit immune escape and get us out of the pandemic.    

1. But isn’t immune escape a concern? We talked about immune escape– the ability of a virus to evade our immune response– most recently in our Q&A of 1/15.  As you’ll recall, immune escape is far more common in the context of disease treatment rather than vaccination.  We’ve already experienced this situation with SARS-CoV-2’s variants.  Evidence indicates that each of the variants of concern, including B.1.1.7 (UK),  B.1.351 (South Africa), and P.1 (Brazil), likely developed their mutations while replicating in the body of an immunocompromised patient.  The patient’s immune system was fighting the virus but unable to quell it, allowing for the virus to continue to adapt, especially in response to new treatments (for more, see this article from Nature and this recent report from the NY Times).  Stopping the virus from reaching immunocompromised people is imperative for stopping new variants from arising.  And mass vaccination is a key component of stopping the virus from infecting immunocompromised people.
2. But do vaccines stop transmission? The Pfizer and Moderna clinical trials were designed to measure the degree to which the vaccine prevented disease, not the degree to which they prevented infection.  In promising news, real world evidence indicates that not only do the vaccines prevent disease, they also prevent transmission and infection.  Last week, Pfizer announced that real-world data from Israel show the vaccine is 94% effective against asymptomatic infection and 97% effective at preventing symptomatic infection.  It’s increasingly likely that vaccines not only stop disease, but stop transmission too, thereby dramatically reducing opportunities for immune escape. 
3. But what about people only partially vaccinated? Immune escape among partially vaccinated individuals is of concern (see Q&A of 1/17), which is why it is imperative for partially vaccinated people to continue to follow key public health measures like masking and distancing and why it’s also important that everyone completes their vaccination schedule on time.
4. But what about reinfection?  If a variant of concern were to arise that evaded our immune response, even after we were vaccinated, we’d need a booster vaccination.  Here the need would be for more vaccination, not less!  Note: so far, reinfection is rare (see Q&A of 10/14). 

I could write more, but in the interest of time, I’ll conclude with this:  If an individual, including a well-credentialed individual like Geert Vanden Bossche, decides to air concerns and make dramatic calls to action, it is incumbent on that individual to prove their point.  Dr. Vanden Bossche has only provided an idea without evidence.  His idea flies in the face of what we currently know.  It is not up to the scientific community to prove him wrong.  It’s up to him to prove himself right!  On that front, he has failed. 

*Brief summary of the letter: In the letter, author Geert Vanden Bossche posits that the vaccinations we’re rolling out will create a perfect storm by which the virus will face just enough evolutionary pressure that it will evolve to escape our adaptive immune response; that evolution will cause the virus to become more transmissible and lethal.  His solution is to halt all vaccinations until his hypothesis should be proven incorrect AND to only resume mass vaccinations when a new type of vaccine is available– one not yet developed or tested, focused on natural killer cells.