Diphtheria. How effective is the vaccine?

Diphtheria (dif-THEER-e-uh) is a serious bacterial infection that usually affects the mucous membranes of the nose and throat. Diphtheria is extremely rare in the United States and other developed countries thanks to widespread vaccination against the disease. However, many countries with limited health care or vaccination options still experience high rates of diphtheria.

Diphtheria can be treated with medications. But in advanced stages, diphtheria can damage the heart, kidneys and nervous system. Even with treatment, diphtheria can be deadly, especially in children.

Diphtheria and tetanus rates are low in the Western world. The vaccine series, with 3 doses for those 7 and older and 4 for younger kids, shows almost 100% efficacy for tetanus and 97% for diphtheria.

Pertussis cases rose until 2020 in the US, but vaccines since the 1940s have lowered overall numbers. Reasons for recent increases include better awareness, testing, reporting, and bacterial circulation. Acellular pertussis vaccines in the U.S. have shorter protection, and the CDC is investigating if molecular changes contribute to the resurgence.

Studies on pertussis vaccine efficacy show:

• DTaP protects 98% of kids within a year after the last dose and about 71% after 5 years.
• Tdap shields about 73% of adolescents in the first year and around 34% after 4 years.
• Tdap in pregnancy prevents about 78% of pertussis cases in infants under 2 months and 90% of hospitalizations.

References:

CDC. https://www.cdc.gov/vaccines/vpd/dtap-tdap-td/hcp/about-vaccine.html#:~:text=A%20complete%20vaccine%20series%20has,for%20children%20younger%20than%207. Last accessed 01.12.2023.