Source Citation:

New England Historic Genealogical Society; Boston, Massachusetts;
Massachusetts Vital Records, 1840-1911

The vaccine is given to newborns at 6 weeks with boosters at 10 and 14
weeks and 95% of people vaccinated develop an immunity to diphtheria. As a note, 200,000 is the population of places like Amarillo, TX, Tallahassee, FL, and Shreveport, LA (per the 2020 Census).

The diphtheria vaccine was initially developed in Berlin, German in 1890 but wasn’t widely available in the US until the 1920s. Vaccination helped reduce the deaths from 100,000-200,000 per year – in the US alone – in the 1920s to 19,000 in 1945 and to only 14 between 1996 and 2014.