Examining new infections in Germany, researchers found that the rate of cases among fully vaccinated individuals aged 60 and older has risen from 16.9% in July to 58.9% in October.
Offering a clear assessment that fully vaccinated people are increasingly becoming the source of Covid transmission, the study identified a similar situation in the UK. Throughout Britain, the number of household contacts exposed to unvaccinated cases (23%) was slightly lower than the number exposed to vaccinated individuals (25%).
In the space of three weeks in Britain, 100 Covid cases were reported among individuals who are 60 or older. Out of those infections, 89.7% of people were fully vaccinated, while 3.4% were unvaccinated.
More concerning for researchers, in Israel, an outbreak that infected multiple healthcare workers and patients, as well as their family members, came from a fully vaccinated hospital patient.
Backing up the fears expressed in the study, the US Centers for Disease Control and Prevention (CDC) currently lists four of the five areas across the US with the highest percentage of fully vaccinated individuals as high transmission counties.
Researchers warned that decision makers must acknowledge the risk that is still posed by vaccinated individuals.
The research released in The Lancet comes as countries weigh imposing Covid vaccine mandates to help protect citizens from the spread of the omicron variant and a potential resurgence in case numbers. Greece became the first nation in the EU to implement a Covid vaccine requirement, threatening all over-60s who don’t get the jab with a monthly fine.