Then I would expect amazing declines this year in other communicable diseases, such as TB and malaria, after the demonstrated effectiveness of their lockdown for COVID.
Those are not good examples, because they both have been eradicated from the US, and are reportable diseases. So public health officials watch for those and take appropriate measures. In addition, malaria is spread by mosquitos, which are notorious for not practicing social distancing.
I have seen some reports that influenza rates have dropped, which makes sense since it is also a respiratory disease. Other causes of death have also declined, since people are staying in their homes and not having as many accidents.