Why is this happening again in Europe after the Delta wave passed through and high rates of vaccination were achieved? There are a few important reasons. First, there are a large proportion of unvaccinated individuals in each country, and only countries such as Spain at 80% and Portugal at 88% that fully vaccinated their total populations have set a high bar and have thus far withstood the continental trend of rise in cases. Noteworthy is Belgium with 74% fully vaccinated and one of the hardest-hit countries in the world, now at 79/100,000, currently 10th highest caseload globally. That alone tells us 74% isn’t enough, and that prior Covid (without vaccination, what some refer to as “natural immunity”) is unreliable for representing a solid immunity wall against the Delta variant. In fact, it has been projected for Delta that any country needs to achieve 90-95% of its total population fully vaccinated (or with recent Covid) in order to have population-level immunity that covers, providing relative protection, for the others.

Key among the unvaccinated are teenagers and children. For European countries, the UK was slower in starting their vaccination program for teens and that has been suggested as one of the reasons their cases started rising again. There is compelling data from both the UK and United States that children and teens have been a key driver of spread in recent months.

It is noteworthy that we are not dealing with just cases or a “casedemic”. For example, Greece’s cases have now quickly soared to 650/100,000 people and so has their death rate increased. While many countries have “uncoupled” their rise in cases from hospitalizations and deaths, that is incomplete at best, and many infected individuals are getting seriously ill, no less the risk of long Covid which remains under-recognized as to its importance and potential of durable disabling effects.