The U.S. passed its first law regulating the sale of vaccines in 1902, and their use became increasingly common over the next decades, so much so that the 1944 Public Service Act required licenses for biologic products, including vaccines, according to the College of Physicians of Philadelphia’s History of Vaccines. Because the diseases in question afflict children more seriously than adults and because regulation made them increasingly safe, immunization had become a familiar feature of childhood in the U.S by the 1950s. The most common childhood immunizations in that decade were for polio, smallpox, tetanus, diphtheria and pertussis, or whooping cough.

Smallpox, the Disfiguring Killer

Smallpox devastated Europe and the Americas from the Middle Ages. Stefan Riedel, of Baylor University Medical Center’s Department of Pathology, reports that its mortality rate among infants could be as high as 98 percent. English physician Edward Jenner developed a safe and reliable vaccine against smallpox around 1800, the result of what Riedel calls the “first scientific attempt to control an infectious disease” by vaccine. A modified form of Jenner’s vaccine was recommended for young children, starting at a year old, in the mid-20th century. The smallpox vaccine was part of the standard immunization schedule for children until 1972, when the disease was considered eradicated in the United States.

DTP, the Three Hazards

Starting in 1948, children received a combined immunization for diphtheria, tetanus and pertussis, still in use in a modified form. The National Vaccine Program Office reports that, before the diphtheria vaccine, the nation averaged more than 175,000 cases annually of this dangerous respiratory infection. Once commonly known as lockjaw, tetanus causes tightening of the muscles to the point where patients may have trouble swallowing or even breathing, warns the National Vaccine Program Office. Pertussis, or whooping cough, is now given in a vaccine called acellular pertussis, which only contains part of the organism; in the 1950s, however, the vaccine contained the entire pertussis organism. Pertussis is a highly contagious respiratory disease that, as its nickname suggests, causes severe coughing spells, so serious as to lead to broken ribs.

Polio, a Crippling Plague

The U.S. licensed the polio vaccine in 1955; this first generation of immunization against polio used the IPV, or inactivated polio vaccine, replaced in the 1960s by an oral vaccine. In 1952, Jonas Salk and his team created an effective vaccine, and its widespread test in 1954 involved 1.8 million schoolchildren, the largest-scale vaccine trial ever, according to the Centers for Disease Control and Prevention. Salk’s vaccine went into production immediately upon its license from the U.S. government; polio was eradicated in the U.S. in 1979.

Public Health Support

Although vaccines were relatively new in the public consciousness, they were widely accepted in the 1950s. Early opposition to the smallpox vaccine had faded by the early 20th century, according to a history of anti-vaccine movements by the College of Physicians of Philadelphia. Organized anti-vaccine movements did not take hold in the U.S. until the 1970s. On the contrary, the move to develop the polio vaccine was, according to the Centers for Disease Control and Prevention, “a national project,” one in which the public, government and industry cooperated to bring a speedy solution to a frightening problem.