If the flight is cancelled then you can cancel the whole booking. Legally there are a few nuances around that, but I wouldn't worry too much about that at the moment. Even if the flight is not cancelled BA Holidays are cancelling pro-actively bookings simply due to the fact that the booking isn't viable as a holiday any more. So for example if you had booked a flight and hotel package to (say) Paris in mid June this may be technically available for travel but if a city has closed or restricted shops, museums, restaurants, historic attractions then it's just impractical, given the purpose of travel.

Relatively few of my June flights have been changed this far, though I'm sure cancellations will come down the wire before too long, so you can wait it out a bit longer. Judging from other posts in this forum, it seems that 3 weeks before travel, or a just before then, is the decision point for many BA Holiday customers.