Just came across this clip from an interview with Paul Offitt that is relevant here: He claims that, out of all the serious side effects resulting from vaccines in the past that he could think of, all emerged within 6 weeks, so the fact that vaccine trials are required to look 2 months after the second dose before applying for an EUA should mitigate most safety concerns.
As another commenter suggested, one exception could be antibody-dependent enhancement (ADE), in which antibodies induced by the vaccine could enhance the severity of subsequent infection—indeed, this concern was not widely appreciated with the dengue vaccine Dengvaxia until years of post-licensure safety follow-up. But at least the specific mechanism of ADE that is operative in dengue is unlikely to be relevant with COVID-19 (ADE with dengue involves vaccine-induced antibodies against one serotype not being able to neutralize another serotype; the antibodies will still bind to the virus, though, and bring the virus to immune cells, which the virus then infects. But SARS-CoV-2 doesn’t have multiple serotypes, and does not seem to be able to infect immune cells.)
Comparing to other vaccines is helpful. But what about a more outside view of new medical treatments? I’m not sure what the reference class should be, but I think the fact that the mRNA vaccine has never been used before should give us pause.
Just came across this clip from an interview with Paul Offitt that is relevant here: He claims that, out of all the serious side effects resulting from vaccines in the past that he could think of, all emerged within 6 weeks, so the fact that vaccine trials are required to look 2 months after the second dose before applying for an EUA should mitigate most safety concerns.
As another commenter suggested, one exception could be antibody-dependent enhancement (ADE), in which antibodies induced by the vaccine could enhance the severity of subsequent infection—indeed, this concern was not widely appreciated with the dengue vaccine Dengvaxia until years of post-licensure safety follow-up. But at least the specific mechanism of ADE that is operative in dengue is unlikely to be relevant with COVID-19 (ADE with dengue involves vaccine-induced antibodies against one serotype not being able to neutralize another serotype; the antibodies will still bind to the virus, though, and bring the virus to immune cells, which the virus then infects. But SARS-CoV-2 doesn’t have multiple serotypes, and does not seem to be able to infect immune cells.)
Comparing to other vaccines is helpful. But what about a more outside view of new medical treatments? I’m not sure what the reference class should be, but I think the fact that the mRNA vaccine has never been used before should give us pause.