macawake, MSN 2,141 Posts Has 15 years experience. Dec 13, 2020 1 hour ago, myoglobin said: Also, we lack data on the long term effectiveness rate for these vaccines. Even most seasonal influenza vaccines are no more than 40-60% effective https://www.CDC.gov/flu/vaccines-work/vaccineeffect.htm and the antigenic drift of Covid seems if anything higher. Your link explains why the efficacy rate is comparably low for flu vaccines. Despite that, they still prevent a significant amount of morbidity and mortality. Both Pfizer’s and Moderna’s Covid vaccines have much higher efficacy rates than the seasonal flu shots have so I don’t really understand how they relate? I’ve seen no evidence that the SARS-CoV-2 virus has higher antigenic shift than the various flu strains that cause seasonal influenza. Do you have any scientific sources that says it does? Your Medium link does as you mentioned say that the virus has a low mutation rate. They’ve identified 68 strains and it says at the very end that only ONE of them (D614G) is clinically significant. And it also says that this mutation does NOT make the virus more resistant to antibodies. This is good news when it comes to what kind of efficacy we can expect from a vaccine.