Two months later and we can apply @nataliexdean's thread to Europe, too: Germany is back to reporting more than 1,000 new daily cases on average, while the median age of cases has dropped to a new low of 32 years (German source: @rki_de situation reports).
The COVID-19 incidence among the two oldest age groups has not risen (yet), as this @rki_de graph shows (h/t: @christoph_rothe). Also number of patients in intensive care is low and stable so far. 
Part of the increase in cases due to testing? Yes - testing in Germany has just hit a fresh high of 875,000 tests per week. But cases have mostly been rising stronger than testing, pushing the positivity rate from 0.59% to 0.99% temporarily, last week at 0.96%.
Similar to March, a considerable share of the newly found cases are returning travelers from places with a higher incidence overall. In March, they came from Italy and Austria, now from Kosovo, Turkey, Serbia...the travelers tend to be younger people who visit family back home.
Similar developments across EU: In Italy, median age of new cases has dropped below 40 (reuters.com/article/us-hea…). In Spain, which has sometimes more than 5k new daily these days, about 10% are age 70+ though (source: ISCIII).
Now what does all that mean? Rehashing a tweet of mine, we might be witnessing the built-up to a wave of infections that will eventually hit the elderly and cause many new deaths in Europe. Or not. We don't know. We might be able to affect it though.
What have we learned from the U.S in the last two months? I think it's a mixed bag. Infections have been rampant, but New York has not repeated itself yet. 1,000+ deaths per day are terrible, especially from Europe (9 deaths in Germany today), but we can't rule out anything.
