CDC ramps up scrutiny of rare post-vaccination "breakthrough infections’"

These cases represent a tiny percentage of the 66 million people fully inoculated, and experts say they are neither unexpected nor occurring at an alarming rate. Indeed, the rarity of the breakthrough illnesses in the context of the vast scale of inoculations reinforces the encouraging message from public health experts: These vaccines are highly effective, and their rollout has dramatically driven down the rates of sickness and death among the most vulnerable populations first targeted for inoculations... There is no singular explanation for why the virus in rare cases is not neutralized by the vaccine-induced immune response. Infectious-disease experts say the human immune system is complicated, and some people may simply have a weak immune response to the vaccine. In this scenario, it’s not the vaccine that’s the wild card, it’s the patient. Fauci offered that explanation Friday during the White House briefing. The several deaths reported so far among people already fully vaccinated were among elderly individuals who may have had underlying health conditions and may not have mounted a strong immune response when vaccinated, he said.