The DTwP vaccine is a combination immunization that protects against three bacterial diseases: diphtheria, tetanus, and pertussis. DTwP stands for Diphtheria, Tetanus, and whole-cell Pertussis, referring to the type of pertussis component used. This vaccine stimulates the body’s immune system to recognize and fight off the bacteria that cause these illnesses.
Diseases Prevented by the Vaccine
Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae. It can lead to inflammation of the nose, throat, and windpipe. The bacteria produce a toxin that damages tissues, forming a thick, gray membrane in the throat that can obstruct breathing and swallowing. If the toxin spreads through the bloodstream, it can damage other organs, causing heart muscle inflammation (myocarditis), kidney failure, or nerve damage, which can lead to paralysis. Symptoms appear 2 to 5 days after exposure and include a sore throat, fever, swollen neck glands, and difficulty breathing.
Tetanus, known as lockjaw, is a nervous system disease caused by Clostridium tetani, a bacterium often found in soil and manure. The bacteria enter the body through cuts or wounds, releasing a toxin that interferes with nerve signals, leading to painful muscle contractions and rigidity. Initial symptoms involve jaw muscle spasms, making it difficult to open the mouth. These can progress to painful, generalized spasms that arch the back and stiffen the limbs. Complications include breathing problems due to vocal cord tightening, bone fractures from spasms, and pneumonia.
Pertussis, known as whooping cough, is a contagious respiratory infection caused by Bordetella pertussis. It begins with cold-like symptoms such as sneezing, runny nose, and a mild cough, which progresses to coughing fits. These fits can make it difficult to breathe, eat, or sleep, and are sometimes followed by a high-pitched “whooping” sound as a person tries to inhale. Pertussis is dangerous for infants, who face a risk of complications such as pneumonia, seizures, brain inflammation, and even death.
DTwP and DTaP Vaccines Compared
The DTwP vaccine, containing whole, inactivated Bordetella pertussis cells, was historically used to protect against pertussis, alongside diphtheria and tetanus toxoids. Concerns about the reactogenicity, or the likelihood of causing side effects, of the whole-cell pertussis component led to the development of an alternative. This resulted in the introduction of the DTaP vaccine, where “aP” stands for acellular pertussis, meaning it contains only specific, purified components of the Bordetella pertussis bacterium rather than the entire inactivated cell.
DTaP vaccines were developed in the 1980s and 1990s, with Japan introducing the first acellular pertussis vaccine in 1981. The shift to DTaP in many developed countries, including the United States in 1997, aimed to reduce common side effects associated with the DTwP vaccine. Studies have shown that DTaP vaccines cause fewer local reactions like redness, swelling, and tenderness at the injection site, and fewer systemic reactions such as fever, irritability, and drowsiness, compared to DTwP vaccines.
Despite DTaP’s improved safety profile, some research suggests that DTwP may offer more enduring protection against pertussis due to its broader range of antigens. However, due to public and medical community concerns about side effects, a return to widespread use of DTwP in regions that have adopted DTaP is unlikely. Both vaccine types provide immunity against diphtheria, tetanus, and pertussis, but DTaP is now the prevailing choice for childhood immunization in many areas.
How the Vaccine Works and Potential Reactions
The DTwP vaccine works by introducing inactivated components of the diphtheria and tetanus toxins, known as toxoids, and killed whole cells of the pertussis bacterium. These components cannot cause the actual diseases but are recognized by the body’s immune system as foreign. This recognition triggers an immune response, leading to the production of antibodies and specialized immune cells that can quickly fight off future infections if the individual is exposed to the real bacteria or their toxins.
Following DTwP vaccination, common and mild reactions can occur. These include soreness, redness, or swelling at the injection site, which may last for a few days. Some individuals may experience a low-grade fever, mild crankiness, tiredness, loss of appetite, or vomiting. These reactions resolve on their own within one to three days.
More pronounced reactions are less common but can include persistent, inconsolable crying for three hours or more, or a high fever that reaches 103°F (39.4°C) or higher. In rare instances, particularly with the whole-cell pertussis component, more serious reactions like febrile seizures (seizures caused by fever) or hypotonic-hyporesponsive episodes (a temporary state of limpness and unresponsiveness) have been reported. These do not result in long-term effects. Any concerns about vaccine reactions should be discussed with a healthcare provider.