inoculation was far less than acquiring smallpox naturally. modern day eradication eradication efforts were always present in mexican history, but the 20th century showed a more successful plan for research, disease prevention, and vaccination. the vaccination and revaccination act was instated in 1925, making it legally required for citizens to be vaccinated from smallpox and revaccinated every 5 years. this act was installed under the administration of general plutarco elías calles. during the 1920s, mexico's government also published guidelines that federal and local governments had to follow regarding organizing revaccination programs, containing disease, reporting cases, and handling vaccines. these guidelines were all a part of the first mexican health code. these efforts continued into the 1930s, as health care workers in the country worked diligently to eliminate this disease. in 1935, a mobile crew was set up by the federal health service to help. medical professionals and volunteers lending their hands and effectively administered 6 million vaccine doses from 1935 to 1936. in the 1940s, there were a few setbacks. the institute that was manufacturing the vaccine, mexico city's hygiene institute, was using glycerinated lymph. this meant that the vaccine had to be refrigerated in a specific temperature or else it would no longer work. mexico is home to various rural villages that did not have access to the type of refrigeration needed to hold the vaccines. it was very difficult to get the vaccine to the thousands of people living in smaller communities. despite the challenges, the vaccinators hard work resulted in over 28 million vaccines given from 1944 to 1949. however, in 1943, the national campaign to combat smallpox was created, with the slogan, "coordination, uniformity, and generalization." this committee was an action taken towards eradicating smallpox in mexico through campaigning through systematic and routine work regarding the vaccine. they mainly pursued smaller and rural communities that had been harder or had less resources to combat the disease. smallpox was officially declared eradicated from mexico in 1951.