How likely is it to get covid after being fully vaccinated? It can happen, especially during this period, before a population immunity high enough to hinder viral transmission is achieved; but it is a rather rare circumstance, and even rarer is contracting it in a severe form.
The latest data from the US Centers for Disease Control and Prevention, which analyzed the percentage of breakthrough infections (i.e. the infections that arise in fully vaccinated subjects), also to evaluate the impact, on these infections, of the variants of SARS-CoV-2. The verdict is comforting: vaccines are also extremely effective against variants, which do not seem to particularly affect the likelihood of getting sick after receiving both doses.
A very low percentage. Out of about 101 million US citizens vaccinated by April 30, 2021, the CDC received reports of 10,262 infections from 46 states: this means that 0.01% of those totally vaccinated have fallen ill again despite vaccines, in a period of coronavirus circulation was still sustained (355,000 cases in the US, in the week ending April 30). Certainly the number of breakthrough infections has been underestimated, because mild, asymptomatic, or untested cases may have slipped the bill. But the data on hospitalizations and deaths confirm this very positive trend.
Out of 10,262 cases, only 995 (10%) needed hospitalization; among these people, 289 had asymptomatic covid or were otherwise hospitalized for other unrelated health problems. Less than 2% of all breakthrough infections culminated in one death (160 deaths reported by the CDC). Among these people, 28 were asymptomatic at the time of death or died from causes unrelated to covid. The median age of the deceased was 82 years.
Variants effect? Not received. The CDC were able to sequence the genome of 555 covid patients among those infected after vaccines. The incidence of variants among this population appeared to be proportional to that in the general population: in other words, the variants did not weigh too much on the chances of infection after vaccines. 64% of the cases among those sequenced were caused by a variant among those in circulation in the USA, especially the English variant. As of May 1, the CDC decided to monitor only breakthrough infections that lead to hospitalization and death and no longer simple infections, which may not track a large number of asymptomatic infections.