There are already three clinical trials with the BCG vaccine for elderly/adults before the COVID-19 pandemic showing its efficacy against pneumonia, acute upper respiratory tract infection(AURTI), and H1N1 influenza
There many papers regarding trained immunity among children with BCG vaccination but I have been looking for clinical trials with adults, especially seniors since they are vulnerable with COVID-19. And I have found three papers so far.
A randomized clinical trial for bedridden elderly people in Japan in 2003.
BCG re-vaccination significantly reduced the probability of pneumonia.
Prevention of Elderly Pneumonia by Pneumococcal, Influenza and BCG Vaccinations
https://medical.nikkeibp.co.jp/inc/all/hotnews/archives/237265.html (A little detailed article in Japanese)
No BCG strain info obtained but I guess this trial was done with the BCG Tokyo strain since it was done in Japan.
Below is a machine translation of https://medical.nikkeibp.co.jp/inc/all/hotnews/archives/237265.html .