As the Delta variant of the SARS-CoV-2 virus rages, health officials are pushing for more people to get the shots, faster. But is that pushing helping — or is it driving COVID infection rates to move higher, with worse symtoms?
Antibody-dependent enhancement (ADE) is a known concern after vaccination for several viral diseases, for example, measles. For vaccines still in development, it’s also come to the forefront in the quest to find the best and safest vaccine for dengue, Zika and HIV, as well as the earlier SARS-Co-V.
What happens with ADE is that when a vaccinated person becomes infected with a variant of the virus they’ve been vaccinated against, they become sicker than their unvaccinated peers who get the variant. Scientists discovered that this can happen with the dengue vaccine, for example. Until recently, because the COVID shot has only been used for a few months, it was unknown whether ADE could occur with it.
But now, researchers using molecular modeling have found that ADE is indeed a risk with the COVID vaccine. “Since our data indicate that Delta variants are especially well recognized by infection enhancing antibodies targeting the NTD (N-terminal domain of the SARS-CoV-2 spike protein), the possibility of ADE should be further investigated as it may represent a potential risk for mass vaccination during the current Delta variant pandemic,” the study authors warn.
Although this same reaction could be possible after natural infection with the Wuhan strain, “with the emergence of the Delta variant, the possibility remains of being confronted with ADEs during a vaccination / infection cycle, especially since it is now established that vaccines do not fully protect against viral infection,” News-in-24 explains.
SOURCES:
Journal of Infection August 9, 2021
News-in-24 August 13, 2021