Why are Covid cases so high when vaccination is widespread?

LONDON — Looking at the Covid case data in the U.S., U.K. and the rest of Europe, you’d be forgiven for thinking that, despite 18 months of a global health crisis and advanced vaccination rollouts, we’re in just as bad a situation as we ever were.

Certainly the number of Covid cases being recorded daily in the West remains high, and even resembles earlier peaks at different points, or Covid waves, during the pandemic.

The current 7-day moving average of daily new cases stands at 153,246, an increase of 4.9% compared with the previous 7-day moving average (of 146,087). The current 7-day moving average is 123.6% higher than the value observed around a year ago, according to data compiled by the Centers for Disease Control and Prevention (CDC). In total, more than 40 million Covid cases have been counted in the U.S. since the pandemic began.

Case rates in the U.K. also remain high. As of Sept 6., the seven-day average of daily new cases was almost 39,000 and the number of daily cases has remained high as the week has progressed; almost 40,000 new cases were reported on Wednesday, and around 38,000 cases were recorded on Thursday, government data showed.

In the EU + EEA area (a total of 30 countries), in the seven days up to Sept. 5, 405,774 new cases were recorded, according to the European Centre for Disease Prevention and Control, with Ireland, France, Sweden, Portugal, Greece and Bulgaria among the countries reporting the highest numbers of new cases per 100,000 population.

The high numbers of cases remains attributable to the spread of the highly infectious delta variant, which usurped previous variants that themselves were more infectious than the original strain of Covid-19.

Nonetheless, the rise in cases has accompanied the advancement of vaccination programs in the West with the majority of adults in both the U.S. and Europe now fully vaccinated.

In the U.S., 62.4% of all people over 12 years of age are fully vaccinated, CDC data shows, while over 82% of over-65s are fully protected. In the U.K., 80.4% of the population over the age of 16 are fully vaccinated and in the EU/EEA, 70.4% of adults have received two doses of a coronavirus vaccine, ECDC data shows.

Crucially, the number of hospitalizations and deaths accompanying the high number of cases has remained lower (and for some countries, much lower) than at earlier points in the pandemic when vaccination rates were much lower, proving that the coronavirus vaccines in use in the West dramatically lower the chance of a severe infection, hospitalization and death. Hospitalizations in the U.S. remain high, data from Our World in Data show.

Yet none of the vaccines in use in the U.S. or Europe is 100% effective, meaning that some vaccinated people will get Covid (so-called “breakthrough cases”) and a small number of those will get sick….