Whooping Cough: Not Just For Kids

Remember the last time you had a regular cold followed by weeks of annoying, dry coughing? Did it ever cross your mind that your problem might be whooping cough? Most likely, neither you nor your doctor gave the diagnosis a minute’s thought. Isn’t whooping cough is one of those childhood diseases, like measles and chicken pox, that immunizations have largely defeated? Yes and no. Yes, whooping cough is a serious illness in babies and toddlers, but it also afflicts adolescents and adults of all ages. And no, the disease has not gone the way of the dinosaurs, though immunization of babies and toddlers has dramatically cut morbidity and mortality rates from the infectious illness.

What is whooping cough?

Whooping cough is a highly infectious respiratory disease caused by the bacterium called Bordtella pertussis. The symptoms of whooping cough begin a week or so after exposure to someone who has the illness. At first, the stuffy, runny nose and mild cough, with little, if any, fever seem like ordinary cold symptoms. But within ten to fourteen days paroxysms of more severe, unproductive coughing begin. Coughing lasts, on average, six weeks. While coughing paroxysms are the signature feature of the illness in all age groups, older children and adults may lack the “whoop” on intake of breath that gives the illness its name.

Babies can die; adults break ribs

In babies and children coughing bouts are frequently followed by vomiting. Infants can quickly develop respiratory distress and pneumonia, and most whooping cough fatalities occur in babies. Older children and adults suffer less severe disease, but the intensity of coughing can make life miserable for weeks, and can lead to hernias and broken ribs. Antibiotic treatment with erythromycin works, but only if the disease is suspected and confirmed early – before the worst of the coughing begins.

Many cases go undiagnosed

Many cases of whooping cough go undiagnosed because people do not seek medical help, or because the diagnosis is unsuspected. Even when whooping cough is suspected as the cause of a chronic cough, accurate laboratory diagnosis is difficult. By the time persistent cough finally brings people to the doctor, a throat or nasal swab may not pick up any bacteria. In addition, routine laboratory culture methods don’t work for pertussis bacteria like they do for streptococcal infections. Proof of infection can be inferred by the presence of blood antibodies against the bacteria, but blood tests to measure titers of are expensive and seldom done.

Vaccine development cut the death rate

Whooping cough occurs worldwide and causes an estimated 300,000 deaths per year across the globe. In the United States, death rates were in the 5,000-10,000/year range between the 1920s and 1940s, but the development of a pertussis vaccine reduced that toll enormously in the latter half of the 20th century. Recently, however, increasing numbers of whooping cough cases are being reported. In 2010 California declared a whooping cough epidemic based on 9,477 confirmed, probable and suspected cases. Washington State did the same in 2012. By that year, 48,000 confirmed cases were reported across the country. At the height of the California epidemic, there were 10 deaths – too many for a preventable disease, but a far cry from the tolls of the past.

Natural cycles, parental backlash and a changed vaccine

Bordtella pertussis has never disappeared from its niche in the human population, and several factors are at work in the recent, apparent increase in rates of infection. Foremost is a natural bacterial population cycle. Whooping cough bacteria seem to increase their numbers in 3-5 year cycles which probably correspond to naturally declining immunity in a population as children get older. This natural variation has coincided with some parental backlash against vaccinations because of fears that they do more harm than good, though childhood immunization rates as a whole are still very high. A third factor may be weaker population immunity because of alterations made to whooping cough vaccine in the 1990s.

Clearly, the original pertussis vaccine, derived from whole, dead pertussis bacteria and delivered as part of the first series of a baby’s shots, helped produce immunity sufficient to make death rates among babies drop dramatically. But in the early 1990s, the formulation of the vaccine was changed to decrease adverse responses to it – responses like fever, swelling at injection sites and rare cases of encephalitis. That change may be responsible for lessened immunity and more whooping cough cases among older schoolchildren. It also raised the number of shots that must be given over several months to achieve immunity in a baby.

Should drug companies fund vaccine research?

Some people who worry that too many vaccines are now being required and are less effective than advertised claim that the makers of the vaccines are anxious to find reasons to give booster shots to as many people as possible. Indeed, the largest and most influential of the scientific groups studying whooping cough – the Global Pertussis Initiative (GPI) – is funded by vaccine makers. But Dr. James D. Cherry has been studying whooping cough for several decades and maintains that the monetary sponsorship by pharmaceutical companies is necessary. Compiling data about infection rates and vaccine efficacy is expensive and surprisingly difficult. The prevention and treatment of infectious diseases depend on accurate assessment of disease rates and currently public health surveillance and reporting is hampered by lack of uniform standards for the diagnosis of whooping cough, especially in older children and adults. In addition, the development of vaccines is extraordinarily complicated and expensive, and will be of increasing importance as antibiotic resistant bacteria continue to evolve and thrive.

Who needs to be concerned about whooping cough?

Whooping cough is of most concern to people who work around and live with small babies who are too young to have completed their series of early DTaP immunization shots (against diphtheria, pertussis and tetanus). The booster vaccination has little risk and is probably advisable for all adults who are in regular close contact with susceptible infants. In the meantime, if you develop one of those miserable chronic coughs after a cold, stay away from vulnerable babies who have not yet had all their shots.

Posted by medical plaintalk

Physician turned medical writer.

More On Shingles

Readers wanting to know more about some topics pose very good questions. My original magazine column about immunization to prevent shingles (September 2011) generated enough reader mail to warrant another column sharing some of the answers.

Recognizing recurrent shingles episodes:

One reader had suffered through an eruption of ophthalmic shingles, which involves the nerve that carries sensation from the eye, including the cornea, from the skin around the eye, and also from the forehead. The reader wanted to know “What are the signs and symptoms for a re-occurrence of the zoster virus in the eye so I would know what to look for if I am getting an attack?” As in other areas of the body, symptoms that come before the rash erupts in the eye and the face are sensory – tingling, burning, itching and pain. Warning sensations in ophthalmic shingles might also include irritating dryness and a sense something lodged in the eye. Our reader understood that taking an antiviral drug early in the course of an eruption might lessen the likelihood of scarring of the cornea, so paying attention to early symptoms has therapeutic consequences. If an abnormal sensation persists for several hours without explanation or response to simple measures like rinsing the eye out, then the symptom is worth bringing to the attention of the doctor. That said, the use of antiviral drugs early in the course of a shingles outbreak does not prevent the eruption from progressing, but it may shorten the duration and lessen its intensity. When the surface of the eye is involved, anything that can be done to prevent corneal scarring is of some value.

Drugs that make the virus awaken

The same reader also wanted to know what drugs might predispose her to another eruption, and how to avoid them. The drugs that put people at most risk for a herpes zoster outbreak are the ones that suppress the function of immune cells in the body. The most common offenders belong to the steroid class on anti-inflammatory drugs, and have names like prednisone, dexamethasone, decadron, and prednisolone. They are used to treat conditions like multiple sclerosis and lupus and rheumatoid arthritis and when used for periods longer than a week, they begin to impair immune response. Sometimes they are part of a chemotherapy regimen for cancer. Other chemotherapy drugs and radiation also impair immune cell function, so shingles eruptions are not surprising in patients undergoing cancer treatment. Paradoxically, steroids are part of the treatment for shingles – but they are used for only a short time, to decrease inflammation.

Vaccine questions

Another reader wrote:” My husband never had Chicken Pox and yet he did have a severe case of shingles and he was in his 40’s when they occurred. At that time we were told the opposite of the article…we were told he got shingles because he had never had Chicken Pox. This was over 20 years ago so perhaps research has changed that. Does the fact he had shingles mean he cannot get the vaccine?” There are many people whose childhood chicken pox was so mild that they have no memory of the disease. Blood testing will show whether or not there is any trace of immunity to the virus in people who think they did not have the disease. An adult who contracts chicken pox for the first time has a rash that involves much more of his body than the shingles rash does. He is also extremely sick, much more so than a child with the disease. So if an adult develops what is a typical shingles rash, it is considered proof that he has had chicken pox in the past.

You probably did have chicken pox

Age 40 is on the young side for shingles, but there are many idiosyncrasies in the immune system, with some people have worse immune “memory” for specific viruses than others do. Having had a shingles eruption does not prevent this reader’s husband from getting the vaccine, and given that it is now over 20 years since the last time the virus stimulated his immune system, immunization might be a very good idea. Guidelines for vaccine administration also do not exclude people who think they did not have chicken pox as a child, even though, in theory, a vaccine made from a live, weakened virus could cause a full blown case of chicken pox in a chicken pox virgin (more on different vaccine constructions below). It is estimated that 99% of people in the US have had chickenpox, whether or not they are aware of it.

Being refused the vaccine

Getting an immunization proved difficult for another reader. He went to his county health department seeking a shingles immunization, but he was turned down because he has non-Hodgkin’s lymphoma, a form of lymphatic system cancer. While his disease is in remission and his blood work indicates good immune cell function, there is a theoretical risk that the vaccine, which contains a live, weakened version of the virus, will reactivate the line of white cells that caused his lymphoma. Many people face this type of risk-balancing problem in choosing whether or not to get a vaccine, and each individual case requires weighing risks versus benefits. In some cases, for example someone with AIDS who has good white blood cell tests and is not sick, the patient’s doctor may advise getting the vaccine because the risk of the effect of a shingles outbreak is greater than the risk that the virus in the vaccine will cause trouble. In the case of people with history of cancers that arise directly from immune system cells, however, no one wants to take a chance of triggering cells to become cancerous by the introduction of a live virus in the form of a vaccine. In addition, no one wants to introduce an infection that the immune system cannot control. These problems are the reason that researchers have pushed to develop a new vaccine, just becoming widely available in in 2017-18, which does not contain any live virus.

The old and the new vaccines

Lastly, several readers inquired about the frequency of the zoster vaccination. Immunizing for shingles is relatively new, and recommendations may change, but right now, Zostavax, the old vaccine, is recommended for all people over age 60, as a one time shot. Zostavax cuts the rate of shingles by 51% and the development of post-herpetic shingles pain by 65%. The new vaccine, Shingrix, is recommended beginning at age fifty and in tests improves these prevention rates to 98% and 85% respectively. Shingrix requires two separate doses. The effectiveness of the vaccines does wane over time, and there is more experience with the old one. Currently there are not any guidelines about repeat administration, but there are no contraindications to getting the new vaccine for people who have already had the old one.

Where to get immunized

Immunizations are available at pharmacies, grocery stores, county health offices, and walk in clinics and all of these facilities have guidelines which will exclude some people. Anyone excluded by general criteria should review the reason with a doctor who cares for the problem that caused the exclusion.

Posted by medical plaintalk

Physician turned medical writer.

Tetanus: Poster Child for Preventive Medicine

True preventive medicine is an intervention that stops a disease from developing, not one which simply slows disease progress. The body’s immune system is the master of disease prevention and it is no accident that one of the first medical efforts at preventing disease stemmed from the observation in the late 1700s that suffering a mild infection like cowpox prevented a similar but more severe infection – smallpox. Immunization was born, and to this date is the single most effective form of prevention of lethal disease. In the current age of rejection of routine immunization by a significant number of people, the disease called tetanus and its prevention by immunization is a story worth reviewing.

What causes tetanus?

Tetanus a disease is caused by a type of bacteria called Clostridia tetani, a fragile little organism that can’t tolerate oxygen or high temperatures but which changes itself into a tough intermediate form called a spore to lie in wait for potential victims. C. tetani spores survive indefinitely, are common in soil, particularly manure rich soil, and are found in intestinal tracts of farm animal, cats, guinea pigs, rats and people. They can survive oxygen rich environments, the usual antiseptics and even the temperatures used to sterilize medical instruments. Once the spores gain entry into body tissues, they revert to fragile bacterial form, reproduce and begin to manufacture tetanospasmin, one of the most lethal toxins known to man and the substance responsible for the symptoms of the disease. Though farm animals and people are susceptible to tetanus infection, dogs and cats are not.

Development of symptoms

Tetanus infections are usually acquired when C. tetani spores enter the body through a deep wound in the skin that air does not reach. Contaminated batches of heroin are also sources of infection when the drug is injected under the skin or intravenously. In the first few days after C. tetani spores come to life inside the body, no symptoms or tests indicate anything amiss. As the toxin producing bacteria increase in number, and the toxin produced finds its way to the spaces between nerves and muscle and between motor nerve cells in the brain and spinal cord, profound muscle spasms begin. Tetanospasmin works by the blocking normal neurochemical signals that inhibit muscle tone and motor nerve excitability.
The time from infection to development of symptoms in any infection is known as the incubation period. In human tetanus, the closer the entrance point of the bacteria to the brain or spinal cord the shorter the incubation period. On average symptoms begin about a week after injury. Though localized forms of tetanus can occur, with muscle spasm limited to the area around the wound, most cases are general and symptoms begin in the muscles of the head and neck. Spasm of the powerful masseter muscles of the jaw is the origin of the term “lockjaw,” a commonly used name for tetanus infection. Vocal cord and respiratory muscle involvement can interfere with breathing. Abdominal, trunk and skeletal muscle involvement are extremely painful and spasms can be strong enough to fracture long bones and spinal vertebrae. Other complications arise from involvement of the central nervous system: fever, high blood pressure, heart rhythm abnormalities and seizures. Secondary complications like bladder infections, pneumonia and blood clots in the legs and lungs also contribute to the lethality of the disease. In the pre-immunization era, treatment was confined to supporting the patient through the four weeks it takes for the toxin’s effects to wane.

Making the immune system remember the disease

Unlike cow pox, in which the natural immune response directed against the cowpox virus prevents more cowpox episodes but also smallpox, a full-blown case of tetanus does not confer any immunity because the minute amounts of toxin that produce the symptoms are not sufficient to stimulate the immune system to make antibodies against it. Immunization to tetanus is accomplished by presenting the immune system with a much larger amount of a formaldehyde weakened version of the toxin, to which it will produce antibodies which will neutralize the real toxin should it ever appear. This process takes a few weeks and several doses are required over time to reach full potency of an antibody response.

Immunization programs have made tetanus rare enough for people to forget how terrible an illness it is. In the US, since routine, active immunization began in the 1940s, tetanus rates declined steadily and were at an all-time low of .01 cases per 100,000 people in 2009. In addition, with better supportive care, mortality rates declined from 30% in the mid-1900s to 10% in the first decade of the 21st C.

Borrowing someone else’s immunity

Nevertheless, tetanus infections still occur and may increase in frequency if immunization rates drop. Fortunately, another type of immunization helps when tetanus develops in people who have not been immunized – a passive immunization process that allows patients to borrow antibodies produced in the blood of other people who have been immunized against C.tetani. This “antitoxin” is a mixture of human gamma globulin from screened donors and antibodies in it that “recognize” tetanus toxin react with the toxin circulating in the tetanus victim’s body, neutralizing a lot of its potency.

Boosting weakened immunity

The antibody response to tetanus toxoid wanes over time, but a repeat injection brings it up to full speed quickly. Booster doses are recommended for all adults every 10 years and in the event of penetrating wounds, especially if immunization status is unknown. Awareness of the symptoms of tetanus and the status of immunization of anyone someone suffering from heroin addiction, a sad and growing problem, is crucial for anyone who cares for them. Tetanus is the poster child for preventive medicine and no one should have to suffer this disease. The earlier it is recognized, the better the outcome is likely to be.

Posted by medical plaintalk

Physician turned medical writer.

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