about VIRUSBREAKEND output

[hidehitofukushima]

Hi, I'm using VIRUSbreakend recently with human tumor genome aligned with hg38 , thankfully it runs without any error, but in most of my dataset, ${TUMOR}.vcf.summary.tsv is empty and the vcf file only has header like this.

##fileformat=VCFv4.2
#CHROM POS ID REF ALT QUAL FILTER INFO FORMAT

But, ${TUMOR}.vcf.kraken2.report.viral.extracted.txt has raised candidate viruses like bellow.

0.00 2509 2509 S 11676 Human immunodeficiency virus 1
0.00 182 182 S1 11099 Bovine viral diarrhea virus 1
0.00 24 24 S1 11053 Dengue virus 1

Is this normal? Vcf is empty because VIRUSBREAKEND raised these viruses only as candidates and re-cauculated concordant reads from scratch?

thanks in advance!
Hidehito