Lots of viruses are really oncogenic. The real success here is the ability of Denmark to track effectiveness. It sounds crazy but most countries do not have electronic health record capability to measure the effect of many interventions at population scale. Once good EHRs are rolled out, we will be able to double down on effective interventions, like this one, and vice versa.
"Lots of viruses are really oncogenic." Hmm. Compared to what measurement? Most viruses are actually not oncogenic. From cancer causes, oncogenic viruses are thought to be responsible for about 12% of human cancers worldwide: https://www.mdpi.com/2079-7737/14/7/797 From what I remember, most viruses are not oncogenic in nature, so I am unsure whether the statement made is correct.
E.g. EBV is strongly associated with several lymphomas.
There are other significant clinical associations for HPV, HBV, HCV, HTLV-1, HHV-8, and many others.