Adacel is a booster vaccine that protects against three bacterial diseases: tetanus, diphtheria, and pertussis (whooping cough). It belongs to a class of vaccines called Tdap, and it’s FDA-approved for people ages 10 through 64. Adacel is manufactured by Sanofi Pasteur and is one of two Tdap vaccines available in the United States.
The Three Diseases Adacel Prevents
Tetanus is caused by bacteria that enter the body through cuts or wounds. It triggers severe muscle stiffness and spasms, particularly in the jaw (sometimes called lockjaw), and can be fatal. Diphtheria attacks the throat and airways, creating a thick coating that makes breathing difficult. Pertussis, better known as whooping cough, causes violent coughing fits that can last for weeks and is especially dangerous for infants too young to be vaccinated.
Adacel works by exposing your immune system to inactivated versions of the toxins these bacteria produce, along with small pieces of the pertussis bacterium itself. Your body learns to recognize these threats and builds antibodies against them. If you’re later exposed to the real bacteria, your immune system can respond quickly. This is a booster vaccine, meaning it’s designed to reactivate immunity you first developed from childhood vaccinations (the DTaP series), not to build immunity from scratch.
Who Should Get It
Adacel is approved as a single booster dose for people ages 10 through 64. Most adolescents receive it around age 11 or 12. After that, routine boosters against tetanus and diphtheria are recommended every 10 years for life.
Pregnant individuals are a key group for this vaccine. The CDC recommends getting a Tdap booster during each pregnancy, ideally between 27 and 36 weeks of gestation, with earlier in that window being better. The goal is for the parent’s body to produce antibodies that cross the placenta and give the newborn temporary protection against whooping cough during the first couple of months of life, before the baby is old enough for their own vaccines. Tdap can also be given earlier in pregnancy if there’s a pertussis outbreak or a wound that needs tetanus protection.
How Effective It Is
A large meta-analysis of acellular pertussis vaccines found that the initial effectiveness of an adolescent Tdap booster is about 85%. That protection, however, fades relatively quickly, declining by roughly 12% per year. One year after receiving a Tdap booster, adolescents had a 70% lower risk of pertussis compared to those who only had their childhood vaccine series. This waning protection is a key reason health authorities recommend the vaccine during every pregnancy rather than relying on a single dose years earlier.
Protection against tetanus and diphtheria tends to be more durable. The toxoid components of the vaccine produce strong antibody responses that hold up well over the 10-year booster interval, which is why routine boosters on that schedule are considered sufficient for those two diseases.
Adacel vs. Boostrix
The only other Tdap vaccine available in the U.S. is Boostrix, made by GlaxoSmithKline. The two vaccines protect against the same three diseases but differ in a few ways.
- Age range: Adacel is approved for ages 10 through 64. Boostrix is approved for ages 10 and older, with no upper age limit. For adults 65 and older, Boostrix is the only FDA-approved option.
- Pertussis components: Both contain inactivated pertussis proteins, but in different amounts and combinations. Adacel includes four types of pertussis antigens, including one (fimbriae types 2 and 3) that Boostrix does not contain. Boostrix has a higher dose of pertussis toxin (8 micrograms vs. 2.5 micrograms in Adacel).
- Diphtheria content: Boostrix contains slightly more diphtheria toxoid (2.5 Lf vs. 2 Lf in Adacel).
Both vaccines contain the same amount of tetanus toxoid. In practice, either vaccine is considered appropriate for the overlapping age group (10 through 64), and the CDC does not express a preference between them for routine use in that range.
What to Expect After the Shot
Adacel is given as a single injection into the muscle of the upper arm. The most common side effect is pain at the injection site, which the majority of recipients experience. Redness and swelling at the injection site are also common but typically mild. Systemic reactions like headache, body aches, tiredness, and mild fever can occur in the days after vaccination. These side effects generally resolve on their own within a day or two.
Serious reactions are rare. People who had a severe allergic reaction to a previous dose of any tetanus, diphtheria, or pertussis vaccine should not receive Adacel. The same applies to anyone who experienced brain swelling (encephalopathy) within seven days of a prior pertussis-containing vaccine that wasn’t explained by another cause.
How It Fits Into the Vaccine Schedule
Children in the U.S. receive a five-dose series of DTaP (the childhood version, which contains higher amounts of diphtheria and pertussis components) between 2 months and 6 years of age. Adacel and Boostrix then serve as the follow-up boosters starting at age 10 or 11. The lowercase “d” and “p” in “Tdap” indicate that the diphtheria and pertussis doses are reduced compared to the childhood vaccine, which is appropriate for older adolescents and adults.
After your Tdap booster, the current recommendation is a booster containing tetanus and diphtheria protection every 10 years. That booster can be either a Td vaccine (tetanus and diphtheria only) or another dose of Tdap. If you need a tetanus shot for wound care and it’s been five or more years since your last dose, a Tdap or Td vaccine can be given regardless of how long it’s been since your previous booster.