Li and his team extracted the virus from the rabbits and injected it into a second group of rabbits, then repeated the process for more than 1,000 viral generations. By slowly domesticating the virus in this way, the researchers developed a less virulent strain. They then injected this attenuated virus into pigs, inoculating them against the disease. Such attenuated-virus vaccines are still in wide use today.
李崇道率領團隊抽取兔子體內的豬瘟病毒，再打入第 2 隻兔子體中，如此經過 1,000 代以上，將病毒慢慢馴化到幾乎沒有毒性，再以此病毒為豬隻注射，就可以達到免疫效果，迄今民間仍大量使用這種減毒疫苗。