you need to finish the mission chain before. At the end, you get a vaccine. Without, you'll allways die.
Read this guide:
https://www.planetcalypsoforum.com/forums/showthread.php?218104-Vaccine-mission&p=2824775&viewfull=1#post2824775
It's no DNA part. DNA parts have clear information about it in Item Info window. Have also looted one a while ago and asked in PAF about. Looks like it is needed for a BP.
Also having an older card and normaly play on high settings with it. Don't think it has to do with older/newer cards. Have set draw distance shorter, but that don't solve problems