The clear failures in the European response to the pandemic and vaccine rollout has undoubtably had a negative effect on the Euro/Dollar exchange rate, as forecasts for economic recovery in the Euro zone have been pushed further back.
The progress being made in both the UK and the US has only highlighted the dichotomy between Europe and the rest of the Developed World in respect of vaccine logistics.
Since the start of 2021, the currency has fallen from €1.235 in early January to a low in April of €1.17, but in the last two weeks has risen back towards the €1.20 level.
The largest traders  have been nowhere near as bullish as price gains might imply. In the last month they have established no new long positions, merely covering short positions. The Euro appetite appears to have come from asset managers, who have been buying European equities aggressively for most of the last year.
But the backdrop remains poor for the Euro, the economic situation remains challenging, whilst interest rate differentials still heavily favour the Dollar (making it costly to be long Euros), whilst the ECB has stated publicly on many occasions that it does not want the currency to rise, with verbal intervention consistently arriving once the unit goes above €1.22, which appears to be the pain threshold.
For now, the unit is struggling to breach €1.20, with further resistance around €1.2030-40 and this is the obvious stop-loss level.
There is also a large outstanding option in Euro/USD at €1.20 for May 7th expiry and big option positions often act as attraction points for market prices.
On the downside, a new low for the recent downtrend (around €1.165 or so) would provide a good exit point for bears, giving a risk/reward ratio of around 5:1. (currently the Euro is currently around €1.1985).
The first hint that the bears are back in control will come with a sustained move below €1.1940, which would be likely to prompt a renewed burst of selling, which in turn would prompt trend followers (speculators) to get short the Euro.
There is long way to go before bearish sentiment reaches the extremes set in February 2020, when they were net short 145,000 Euro futures contracts. Currently, they are short just 12000.
 The importance of the larger traders is two-fold- they did not get large by being wrong (for very long) and by dint of being large, they often have an outsized effect on market conditions. So, they are worth watching for clues about future price direction.