They will not be unaffected, but if you look at their presence in Northern Italy, which is the biggest area in Europe that is taking a hit, they only have 10 routes in summer (4x PSA (9w), 4x VCE (9w), 1xVRN (2w), 1xMXP (6w)), covering less than 4 daily flights. Ryanair, Easyjet (both notably have bases!!!) and pretty much every legacy have far more frequencies to Northern Italy. So in terms of Covid and short-haul flying in Europe, Norwegian might actually be in a slightly better place.
Agreed, they will see a "less intense revenue loss effect", but all of Europe is affected, this includes e.g. UK where Norwegian is highly exposed.
Types flown: A318, A319, A320, A321, A32N, A333, A343, A359, A380, AT42, AT72, B717, B733, B735, B736, B737, B738, B739, B744, B748, B763, B772, B773, B788, B789, CRJ2, CRJ9, ERJ190, MD80s/90, RJ100