The Skin Factor
As more immunizing agents became available, people saw the benefit of immunizing large groups, such as soldiers. During World War I, they were vaccinated against diphtheria; during World War II, typhus and tetanus.
The Future Has a Past
Hypodermic injection remains the most common method of getting through the skin. But it is not the only technology for immunization. Engineers and scientists continue to search for alternative routes into the body, such as through the moth or nose. And continuing to solve the technological problems is critical for countries in which illness and death rates are high as a result of measles, maternal tetanus, and other preventable diseases.
A successful instrument or system must get the vaccine into the body with minimal disruption, and be cost-effective for use with billions of people. And perhaps the most important problem today—preventing reuse of syringes to avoid cross-contamination—was not even imagined in the 19th century.
These devices represent different approaches to immunization. Starting
upper right: reusable glass syringe and plastic case (mid-20th century);
two devices currently in development (one uses microneedles and the
other, intradermal injection); pre-filled single-dose injection device
(2004); nasal spray device that bypasses the skin (2004); disposable
safety syringe (2004); disposable plastic syringe (1990s); disposable
glass syringe (1980s); air-pressure gun (1970s); glass and metal antitoxin
syringe (1930s); glass window syringe and case (1880s; note the thin
wires used to keep the needle barrel open); Sharps container for disposal
of used needles (1990s).