Tripedia was a diphtheria, tetanus, and acellular pertussis (DTaP) vaccine used in the United States to protect young children. Administered as a series of injections, it provided immunization against these three bacterial infections. It was an early DTaP vaccine licensed for infants and young children in the U.S.
The Diseases Tripedia Prevented
Tripedia was developed to defend against diphtheria, tetanus, and pertussis. Diphtheria is caused by Corynebacterium diphtheriae, which produces a toxin leading to a thick, gray pseudomembrane in the throat. This membrane can obstruct the airway, making breathing and swallowing difficult, and may spread to other organs, causing heart, nerve, or kidney damage, and even death. Symptoms include a sore throat, mild fever, and swollen neck glands, typically appearing two to five days after exposure.
Tetanus, or lockjaw, results from a toxin produced by Clostridium tetani, often found in soil. It usually enters the body through cuts or puncture wounds and is not spread from person to person. Tetanus causes painful muscle spasms and stiffness, particularly in the jaw and neck, leading to the characteristic “lockjaw.” Spasms can spread throughout the body, causing severe contractions that may result in bone fractures. Symptoms typically appear between 3 and 21 days after infection, and even with modern medical care, tetanus can be fatal in 10% to 20% of cases.
Pertussis, or whooping cough, is a highly contagious respiratory infection caused by Bordetella pertussis. Initially, symptoms resemble a common cold, including a runny nose, sneezing, and a mild cough. After one to two weeks, the cough progresses into severe, rapid fits, making it difficult to breathe, eat, or sleep. These fits often end with a high-pitched “whooping” sound as the person inhales. Infants are particularly vulnerable, potentially experiencing apnea and developing complications like pneumonia, seizures, or brain damage, which can lead to death.
Why Tripedia Was Discontinued
The Tripedia DTaP vaccine was discontinued in the U.S. in 2013. Its discontinuation was primarily a business decision. Manufacturer Sanofi Pasteur had acquired another DTaP vaccine, Daptacel, from Pasteur Merieux, leading to the decision to discontinue Tripedia.
The landscape of DTaP vaccines has evolved since Tripedia’s initial licensing in 1996. Newer DTaP vaccines, such as Daptacel and Infanrix, became available and offered advantages, including improved manufacturing processes or formulations. These newer vaccines have largely replaced older DTaP formulations, reflecting advancements in vaccine technology. Daptacel and Infanrix, for example, contain inactivated forms of the toxins and antigens from the diphtheria, tetanus, and pertussis bacteria, prompting the body to produce antibodies for immunity.
Understanding Vaccine Side Effects
DTaP vaccines, including current versions like Daptacel and Infanrix, can cause various side effects, typically categorized as mild or more serious. Mild side effects are common and generally resolve on their own. These often include soreness, redness, or swelling at the injection site.
Children might also experience a mild fever, fussiness, tiredness, or a temporary loss of appetite. Some children may also have vomiting after receiving the vaccine. These reactions usually occur within one to three days following vaccination and are manageable with home care, such as applying a warm, damp cloth to the injection site or administering over-the-counter pain relievers if recommended by a doctor.
More serious side effects are rare but warrant medical attention. These can include seizures, a very high fever (above 105°F or 40.5°C), or continuous crying for three hours or more. In older children, swelling of the entire arm or leg where the shot was given can sometimes occur, particularly after later doses. While extremely rare, severe allergic reactions, such as hives, facial or throat swelling, difficulty breathing, or a fast heartbeat, can happen and require immediate emergency medical care.