What is Diphteria?
Diphteria is caused by an infection with the bacterium Corynebacterium diphtheriae. The bacterium can infect the skin, nose and throat. The disease is highly contagious and has a mortality rate of about 10%. Patients who survive the infection can take a long time to fully recover.
During the infection a thick grayish membrane forms in the throat that can make it difficult to breathe. Additionally, the bacterium produces a toxin that can damage the heart, brain and the kidney.
What is Tetanus?
Tetanus is another bacterial infection. It is also popularly called lockjaw. The pathogen that causes tetanus is called Chlostridium tetani. It can live in the soil for years in the form of spores, and infection usually happenes when the spores enter a wound like a cut or scrape. Splinters, or animal bites can also be a source of a tetanus infection.
The bacterium produces a toxin that enters the nerve cells that control skeletal muscles. It basically releases the brakes from the connection between the nerves and the muscles and this causes generalized muscle spasms. These muscle spasms can be so severe that they can interfere or even prevent breathing, leading to death by asphyxiation.
The mortality rate of tetanus can be up to 20%.
What is Pertussis?
Like diphtheria and tetanus, pertussis, also called the Whooping Cough, is a bacterial infection. The bacterium Bordetella pertussis can infect the upper respiratory tract and cause violent coughing spasms. The spasms can cause vomiting, can interfere with breathing and can give the patient a feeling of choking.
The infection usually starts with symptoms similar to those of the common cold, but the coughing becomes more and more severe over the course of the next few weeks. Coughing spasms can appear for several months and recovery is very slow. Pertussis can also cause complications like pneumonia, seizures, brain damage and death. Whooping cough has become more common again in the Unites States since the 1980s.
Vaccination and DTaP vaccine
The immune system, the body’s defense system that protects us from infections with pathogens like bacteria and viruses, has the ability to remember a pathogen that is has encountered before. This memory can be harnessed by substances that are similar to the pathogen on the molecular level.
This fact enables scientists to make vaccines that contain either parts of pathogens, killed pathogens or weaker versions of the pathogen that can’t make us sick, but induce the memory of the immune system. A later infection with the real pathogen will lead to a fast and strong immune response, enabling the immune system to get rid of the intruder, before it has the chance to make us sick.
What is the DTaP vaccine?
The DTaP vaccine is a vaccine that is given to babies and toddlers five times before the age of 6 years. The schedule recommended by the Centers of Disease Control and Prevention (CDC) is a shot each at 2, 4, and 6 months of age and again at 1 ½ years and another one between 4 and 6 years of age. It consists of the diphteria and tetanus toxoids and parts of the bacterium that causes pertussis.
A toxoid is a molecule that is sufficiently similar to a toxin that the immune system can mount a response against it and that will also protect against the real toxin, but it is not poisonous. In the case of the DTaP vaccine the tetanus and diphtheria toxoids cause the immune system to react to them, and if the person who received the vaccine later encounters the real toxins through an infection with Corynebacterium diphtheriae or Chlostridium tetani, the immune system remembers the encounter with the toxoid and will be able to respond strong enough to the real thing to prevent the person from getting sick. The DTaP vaccine also contains parts of the pertussis causing bacterium Bordetella pertussis.
The DTaP vaccine was introduced in the Unites States in the years 1991. Before then another diphtheria, tetanus, and pertussis vaccine was used. It was called DTP, and also contains the diphtheria and tetanus toxoids. However, unlike the DTaP vaccine that only contains certain parts of the B. pertussis bacterium, the DTP vaccine contains killed B. pertussis bacteria. It has a much higher frequency of side effects than the DTaP vaccine and is therefore no longer used in the US.
The use of the DTP and the DTaP vaccines has made diphtheria and tetanus a very rare disease in western countries. However, pertussis infections have become more common since the 1980s. This is in part due to some parents refusing to have their children vaccinated, and it is also due to the fact that the protection from pertussis infection provided by the DTaP vaccine can wear off over the course of several years making teenagers and young adults susceptible to the infection. Since the DTaP vaccine is not approved for the use in children older than seven years, the CDC therefore recommends another diphtheria, tetanus, and pertussis vaccine for children at the age between 11 and 12 years which is called Tdap.
DTaP vaccine side effects
Like all medications vaccines can cause unwanted side effects. However, contracting the disease(s) the vaccine is protecting from, is much more risky and the diseases, the DTaP vaccine prevents, can cause permanent injuries and death in a large proportion of the infected.
The side effects that are encountered most commonly with the DTaP vaccine are fever, and redness, swelling, and pain at the injection site. These can occur in up to 25% of the vaccinated children, but usually go away after a short time without treatment. Swelling of the entire arm where the shot was given, vomiting and tiredness can also happen. Seizures are a more rare side effect and affect about 1 in every 14000 vaccinated.
Severe allergic reactions are extremely rare and occur in less than 1 million vaccinations. However, they can be life threatening and require immediate medical attention.