Diphtheria Vaccine

Far to the north, beyond the mountain range, lies the harsh Boreal Wilds, where your foot has not yet stepped. Beyond the mountains lies the city of Teklanika, which is currently ravaged by diphtheria. And the vaccine that could save the local people was never delivered on time.

Finding the necessary amount of vaccine doses will take some time, but as soon as everything is gathered and packed onto the dog sled, you can go with Gunnar to the Boreal Wilds. In exchange for your help, Gunnar promised to show you a shortcut through the pass so that, in the future, you can travel independently to the new region!

You can get Diphtheria Vaccine from:

• Buy in Deepwater for 20 gold nuggets at the One-eyed Jack's Store. — 1 vaccine/day (the 1st one he will provide you for free).
• Get from a chest at the Cultist Camp after defeating the final boss. — 5 vaccines/week

To get there, you must be a well-prepared and experienced cowboy.

To hit the road to the Boreal Wilds:

• Complete the Marshlands quest chain in the Cultist Camp.
• Finish Chapter V of the Storyline.
• Meet Dr. O’Connor at your Ranch.
• Talk to Leonard Gunnar in the Workers Camp and discover what happened to the Diphtheria Vaccine.
• Gather all of the Diphtheria Vaccines and prepare the dog sled for the trip.

So if you’re strong enough and ready for new adventures, you need to talk to Dr. O'Connor. He will fill you in and direct you to assist Leonard Gunnar.