ADE ANTIBODY-DEPENDENT ENHANCEMENT Indeed, vaccines that produce low titers of neutralizing antibodies elicited more severe disease and higher mortality rates
Impact of immune enhancement on Covid-19 polyclonal hyperimmune globulin therapy and vaccine development
While development of both hyperimmune globulin therapy and vaccine against
SARS-CoV-2 are promising, they both pose a common theoretical safety concern . Experimental studies have suggested the possibility of immune-enhanced disease of SARS-CoV and MERS-CoV infections, which may thus similarly occur with SARS-CoV-2 infection (as discussed below).
The concern with antibody-dependent enhancement (ADE) of CoV infection arose from observations with feline infectious peritonitis virus (FIPV). FIPV infects myeloid-derived cells, such as macrophages, in cats . As the target cell of FIPV also expresses fragment crystallizable (Fc) receptors, antibody decorated FIPV could activate Fc receptors for entry into macrophages. Indeed, vaccines that produce low titers of neutralizing antibodies elicited more severe peritonitis and higher mortality rates in vaccinated kittens . Concerns were also raised on the possibility of ADE for SARS-CoV and MERS-CoV infections .
Concerns were also raised on the possibility of ADE for SARS-CoV and MERS-CoV infections .
Besides dengue, several other viruses have shown clinical or epidemiological evidence to support the notion of ADE. Two notable examples of vaccine-induced ADE are respiratory syncytial virus (RSV) , , ,  and atypical measles [30,31], where severe disease was more prevalent following vaccination with inactivated virions. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161485/#bib0011