Delta ‘blunts jabs’ effectiveness’, casts doubt on herd immunity and could see hoarding
Some vaccines lost effectiveness after three months, which is likely to lead to calls for booster shots
Covid-19 vaccines are less effective against the Delta variant, according to results in the UK from one of the largest real-world studies into the efficacy of the shots.
Pfizer and BioNTech’s messenger RNA (mRNA) vaccine lost effectiveness in the first 90 days after full vaccination, though that shot and the one made by AstraZeneca still staved off a majority of Covid-19 infections. When vaccinated people did get infected with Delta, they were shown to have similar levels of virus in their bodies as those who hadn’t had shots. This suggests vaccinating large portions of a population might not protect those who don’t get inoculated, casting doubt on the idea of achieving herd immunity. ..