Fully Vaccinated People Are Still Getting Infected With Covi
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People who are fully vaccinated against Covid-19 are highly protected against severe infection, hospitalization and death caused by the virus. But coronavirus cases among the fully vaccinated are still being seen among those who have had two doses. While it’s rare for vaccinated people in the U.S. or Europe to get sick from Covid, breakthrough cases are happening for a number of reasons, experts note.

For a start, none of the vaccines being deployed in the U.S. or Europe are 100% effective at preventing infection. In addition, new Covid strains such as the highly infectious delta variant have complicated the efficacy picture. There is also incomplete data into how long immunity from Covid lasts following vaccination.

The alarm was raised over breakthrough Covid cases when preliminary data in Israel published in July found that the Pfizer-BioNTech Covid-19 vaccine was just 40.5% effective, on average, at preventing symptomatic disease. The analysis still found that having two doses of the shot provided strong protection against severe illness and hospitalization, however, the country’s Health Ministry reported.

The Israeli data stands in contrast to a study in England carried out from April to May that found that, after two doses, the Pfizer-BioNTech vaccine was 88% effective against symptomatic disease caused by the delta variant. The English data also concluded that after two doses the Pfizer-BioNTech Covid vaccine is highly effective against hospitalization from the delta variant. In addition, English data found that the Oxford-AstraZeneca vaccine was 92% effective in preventing hospitalization after two doses.

Professor Lawrence Young, a virologist at the University of Warwick’s Medical School in the U.K., told that cases of Covid in fully vaccinated people are a reminder that “no vaccine is 100% effective.There are also two other factors that impact vaccine effectiveness: (1) waning immunity — we still don’t know how long vaccine-induced protective immunity lasts. This is very likely to be a factor in those elderly and more vulnerable individuals who were vaccinated early in the vaccine rollout program,” he noted.

The second factor, he added, related to “breakthrough infections in vaccinated individuals due to the more infectious delta variant” which added weight to the case for booster vaccination programs, he said. As yet, the jury is still out on booster programs with a decision yet to be made in the U.S. and U.K.