Health care was not a priority in the colony's early years. Incredibly, there was no permanent doctor in Russian-America until after the Baranov era. However, with the coming of naval governors, steps were taken to provide better health care. Between 1817 and 1821, hospitals were established at Sitka, Kodiak, Unalaska, and Atka. These offered free treatment to Natives there.
The greatest health issue in Russian-America was the threat of disease to Alaskan Natives, who had no natural immunity to the new pathogens Europeans brought to the New World. Many epidemics swept through Alaska during the Russian-American period, including dysentery, influenza, typhoid, whooping cough, and measles. The worst crisis was a smallpox epidemic that spread from California to Alaska in 1835. By 1840, an estimated 1/4 to 2/3 of Natives in villages across the state had died. During this time, Russians worked hard to vaccinate Natives across the state, which saved many lives.
Across Alaska, Native populations suffered catastrophic drops over the Russian period. Among groups not under their control but with extensive contact with Russians, such as the Tlingit, Cook Inlet Dena'ina, and Prince William Sound Chugach, populations dropped by an estimated 50%. Disease was the principal reason.
The populations under Russian control, the Aleut and Kodiak Island Alutiiq, dropped by a staggering 80%. In addition to disease, warfare, family dislocation, and forced labor in dangerous conditions added to the toll. In 1740, the year before Bering's expedition, the Aleut population was estimated at 15 to 20 thousand. A hundred years later, in the 1840 census, it had dropped to 4,000.