There are some correlations between BCG vaccines (especially the Japanese strain) and covid-19 doubling times[1][2][3]. But these are just correlations so far.

There is also an ongoing study in Australia to try to find if there's really a relationship[4] and some talk about trying a similar trial in Boston[5].

It will probably be while before we see any specific results.

[1] http://www.bi.cs.titech.ac.jp/COVID-19/Death_vs_BCGpolicy.ht...

[2] https://mobile.twitter.com/hshimodaira/status/12474763673707...

[3] https://economictimes.indiatimes.com/industry/healthcare/bio...

[4] https://clinicaltrials.gov/ct2/show/NCT04327206

[5] https://www.nytimes.com/2020/04/03/health/coronavirus-bcg-va...