To those downvoting:

“The most worrisome part, he said, is that antibodies also can make subsequent infections worse, creating so-called antibody-dependent enhancement. Two vaccines — one against a coronavirus in cats and another against dengue, a flavivirus that affects humans — had to be withdrawn because the antibodies they induced caused potentially fatal reactions. If an antibody binds weakly against these viruses or falls to low levels, it can fail to “neutralize” the virus, but instead help it get into cells.”

https://news.berkeley.edu/2020/09/09/for-an-effective-covid-...

Why would anyone down-vote a question asking if there is any merit to some concerns raised by a clinical researcher? The target audience is people working on mRNA vaccines who might be able to shed some light.