In 1969, she came to the United States to be an instructor in the Department of Pediatrics and the Laboratory of Immunology at Albert Einstein College of Medicine in New York, where she met John B. Robbins.

Schneerson advanced from a visiting scientist to a senior staff fellow to a supervisory research medical officer during her time in the Division.

Prior to the vaccine’s use, Hib infected 20,000 U.S. children younger than age 5 each year; 5% died of those, and one-third were left with intellectual disability, deafness, or seizures.

Studies in animals, adult humans, and children documented that injecting the polysaccharide alone could induce protective levels of antibodies to Hib.

In fact, many scientists believed that a polysaccharide-based vaccine would never work because immature defenses of the infant immune system were not savvy enough to detect the polysaccharide and make antibodies.

Schneerson and Robbins tried a new process: They linked the weak polysaccharide to a protein carrier, one that was easily recognized by the immature immune system of infants, in an effort to boost its antigenicity.

The conjugate vaccine for Hib produced high antibody levels, well above what was needed for protection, among infants from injections starting at age 2 months and persisting for years beyond.

Their efforts led to the development and licensing of vaccines against pertussis (whooping cough),[10] typhoid,[11] Staphylococcus[12] infections (pneumonia, aureus,[13] and Group B), certain types of malaria,[14] and anthrax.