Whooping Cough – How Quickly it Spreads

10 12 2012

This Seattle mom shares the story of her infection, and consequently, that of her newborn son.





Whooping Cough Can Happen to You or Your Baby

19 07 2012

Whooping cough comes in waves. It’s not a problem every year, but we’re riding a wave right now.

We were on a telebriefing this morning with Dr. Anne Schuchat, director, National Center for Immunization and Respiratory Diseases (CDC), and Mary Selecky, secretary, Washington State Department of Health.

They reported that Washington state is a reflection of the national picture of this difficult-to-control disease.

Washington is in the midst of an epidemic, with 3,000 cases so far this year and nine infant deaths. Pertussis (whooping cough) is most dangerous for babies, and more than half who become infected are hospitalized.

In the nation, nearly 18,000 cases have been reported to date, with many states seeing higher numbers of infected than normal.

In 2010, there were 27,000 reported cases and 27 deaths, 25 of those who died were infants.

There has been a gradual and sustained increase of reported cases in the US, and the CDC is in the field trying to determine why that is.

Potential causes of increased numbers could be:

  • childhood vaccines provide immunity for a number of years, but that immunity wanes over time
  • there has been increased reporting of disease
  • there has been an increase in diagnosis of pertussis

In this current wave of disease, the highest rates of infection are among babies younger than one. Babies depend on those around to be immunized so that adolescents and adults won’t pass on the infection to the baby, who is too young to be fully protected by immunization.

There are also higher rates of infection in 10-year-olds, because early childhood immunizations have waned. A booster called “Tdap” (tetanus, diphtheria, acellular pertussis) is recommended for children 11 to 12 years old.

One odd thing that’s going on in Washington and elsewhere is that young people ages 13 to 14 years are also experiencing higher rates of infection. A theory as to a possible cause for this is that this group of teenagers is the first to have had acellular pertussis vaccine only as babies and young children, and no whole-cell pertussis vaccine.

In 1997, the switch was made from whole-cell pertussis vaccine to acellular pertussis vaccine in the US.

It’s just a theory. How that might affect immunity, if it does, is being investigated.

Pertussis vaccine is the most effective approach to preventing infection. Unvaccinated kids have an eight times higher risk of infection compared to vaccinated kids.

Vaccinated kids who get pertussis have milder symptoms, shorter illness, and are less infectious.

In 2010, only eight percent of adults in the US had a history of the Tdap booster.

Throughout today’s telebriefing, Dr. Schuchat and Ms. Selecky emphasized the need for pregnant women and all adults and adolescents to be vaccinated to protect not only themselves, but the babies in their lives, as most babies who are infected acquire that infection from adults and teens around them.

This surge in pertussis cases isn’t just in the US. Australia’s rate of pertussis infection right now is even higher than that in the US, and Canada is struggling.

Moms and dads are losing their babies to this disease. Whooping cough is so infectious—you could be infected and pass it on to a co-worker who then takes it home to his newborn daughter.

Because pertussis is underdiagnosed, many people are infected but don’t know it.

Ask your pharmacist, your doctor, or even your employer about getting the pertussis booster shot. Please.

By Trish Parnell

Image courtesy of CDC





Whooping Cough Booster Shot – Gotta Have It!

14 05 2012

(Welcome to the CDC folks again! Today they’re talking about whooping cough and the booster shot kids need.)

Another fitful night. A mom lies awake, listening helplessly as her child coughs and coughs. This mom knows tomorrow will be another day of school missed. Soccer practice missed. And for her, another day of work missed. She wonders wearily when it will end.

This cough is whooping cough, also called the “100-day cough” because of its long duration. And the child? Not an infant, as one might expect, but a preteen, 11 years old.

Whooping cough—or pertussis—is a serious and very contagious respiratory disease that can cause long, violent coughing fits and the characteristic “whooping” sound that follows when a person gasps for air.

Whooping cough has been on the rise in preteens and teens. In 2009, a quarter of the 16,858 cases of pertussis reported in the United States were among 10- through 19-year-olds.

Most children get vaccinated against whooping cough as babies and get a booster shot before starting kindergarten or first grade. But protection from these vaccines wears off, leaving preteens at risk for infection that can cause prolonged illness, disruptions in school and activities, and even hospitalization.

To boost immunity, the Centers for Disease Control and Prevention (CDC) recommends the Tdap vaccine for all 11- and 12-year-olds.

“It’s important for preteens to get a one-time dose of Tdap to protect themselves and those around them from whooping cough,” says Anne Schuchat, MD, director of CDC’s National Center for Immunization and Respiratory Diseases. “Young infants are most vulnerable to serious complications from pertussis and can be infected by older siblings, parents, or other caretakers.” For infants, whooping cough can be deadly.

“Unfortunately, the most recent survey shows that only a little more than half of teens have received the Tdap vaccine,” says Dr. Schuchat. “By taking their preteen to get Tdap, parents can protect their child and help stop this disease from spreading.”

Tdap is one of three vaccines CDC specifically recommends for preteens. The others are the meningococcal vaccine, which protects against meningococcal disease, including bacterial meningitis, and, for girls, the HPV vaccine, which prevents cervical cancer. Boys and young men can get HPV vaccine to prevent genital warts. Of course, the flu vaccine is recommended for everyone six months and older.

Preteens should also be up-to-date on so-called childhood vaccines to prevent hepatitis B, chickenpox, polio, measles, mumps, and rubella.

These recommendations are supported by the American Academy of Pediatrics, the American Academy of Family Physicians, and the Society for Adolescent Health and Medicine.

To learn more, visit CDC’s adolescent vaccine website or call 800-CDC-INFO.





When to Seek Help for a Cough

3 05 2012

As a parent, you may wonder whether you or your child with a cough has pertussis, but when you go to the doctor, he or she may not agree or even suggest testing.

The truth of the matter is that the accurate diagnosis of pertussis is challenging. Classic symptoms such as severe coughing spells and the inspiratory whoop are striking and strongly suggest pertussis, but they are not always present, especially in previously vaccinated or previously infected adolescents and adults. Additionally, as described in Dr. Cherry’s recent post, available tests are most sensitive early in disease when the bacteria is present in the nose, but this is often before pertussis is suspected. Accurate diagnosis also depends upon the likelihood of having been exposed to someone with pertussis. Communities across the U.S. are experiencing pertussis outbreaks and many children and adults present to their health care provider with a cough.

So, how do doctors know what to look for?

Background
Pertussis occurs in ALL age groups but is most severe in young infants. While pertussis-containing vaccines have been available since the 1940s, pertussis outbreaks continue to occur every year in the U.S. The number of reported cases has been increasing steadily since the 1980s, especially among young infants and adolescents. According to the Centers for Disease Control and Prevention (CDC), more than 27,000 people were diagnosed with pertussis in 2010.

Pertussis is most severe in young infants who are too young to have received any or all doses of vaccine; in fact, about 3 of every 4 infants less than 6 months old develop complications like pneumonia or seizures and about 1 of every 100  infants less than 2 months old die. Unfortunately, many infants get pertussis from adolescents and adults who don’t realize that they have it.

Pertussis is transmitted in respiratory droplets by coughing and sneezing, and people with pertussis can be contagious for up to 3 weeks after developing symptoms. Pertussis is so contagious that when someone in the house has it, virtually everyone else in the house that is not immune will also get it. In fact, studies have shown that if ten unimmunized people are in a room with someone who is infected, 8 or 9 of them will also develop pertussis.

Vaccination is the most effective way to prevent pertussis, but protection is not lifelong. Vaccination is highly effective, however, it does not prevent all disease and immunity decreases over time. This is also the case after natural infection and is why even people who have had pertussis before should still get a booster dose. This decreased immunity through time is also why we have seen an increase in pertussis among adolescents and adults.

What Parents Should Look For
The official set of symptoms used to identify cases of pertussis is:

A cough that lasts for at least 14 days and either episodes of multiple, rapid coughs without any break, whooping when breathing in or a cough so severe that vomiting occurs.

However, it is important to realize that symptoms are not always typical, especially in previously vaccinated older children, adolescents and adults. The way that pertussis presents depends upon your age and vaccination status:

Infants and young children
The most ‘typical’ presentation occurs in young children:

  • Stage 1 –   Pertussis starts with mild cold symptoms like runny nose, mild cough and watery eyes  This stage typically lasts for about 1 to 2 weeks.
  • Stage 2 –  Despite resolution of other symptoms, severe cough develops.  ‘Whooping cough’ refers to episodes of multiple, rapid coughs without any break.  The episodes can be so severe that the lungs run out of air resulting in a forced inhalation that sounds like a ‘whoop.’  The cough can also be accompanied by vomiting.    Infants and children can look quite ill when coughing but appear well in between episodes.  This stage can last for 1 to several weeks.
  • Stage 3 –  The coughing episodes begin to resolve and become less common over several weeks  to months.
  • All Stages – Fever is not a major symptom of pertussis.

Babies are less likely to show these classic symptoms. They tend to have coughing associated with gagging or gasping and ”apneic’ episodes, during  which they briefly stop  breathing.  Infants and young children may also turn blue during coughing spells because they can’t get enough oxygen due to the severe, repeated coughing. Young infants may also show no interest in eating and might experience seizures. 

If parents notice any of these signs or symptoms, they should have their child seen by a health care provider right away for testing and antibiotics—this is especially important for young infants since they are at the greatest risk for severe disease. Antibiotic treatment can decrease the duration of symptoms and make them less severe, but it is most effective when given early in the infection.  Antibiotics also help decrease the likelihood of spreading pertussis to others.

Adolescents and adults
Older children, adolescents and adults with pertussis are more likely to have milder symptoms that can mimic other cough illnesses, especially if they have been immunized or previously infected, however, they can still develop severe disease:

  • The primary symptom is often a persistent cough lasting at least 7 days, usually without a fever.
  • Severe coughing episodes and whooping may occur, but is more common in unimmunized individuals.
  • Coughing episodes can be severe enough to cause rib fractures, difficulty sleeping, poor bladder control, damage to the lung cavity and even bleeding in the brain.  Vomiting with cough can also occur and is considered to be highly suggestive of pertussis in adults.
  • The average duration of cough in adults is 1 to 1 1/2 months.
  • Adolescents and adult who recently had pertussis may experience a return of symptoms if they get another respiratory infection shortly after recovering.

Because older children, adolescents and adults are less likely to have typical symptoms, they often are not tested or treated, and unknowingly spread pertussis to others. Pertussis should therefore be considered in anyone with a coughing illness with no fever or a mild fever, especially if they have been around someone with pertussis or a cough illness or they have regular contact with infants and young children who are at risk for severe disease.

A Final Word about Testing
Testing for pertussis is most sensitive in the first 3 to 4 weeks of infection. Bacteria that cause pertussis can usually be detected from the very beginning of the illness through the first two weeks of the cough stage; however,  in people who have been vaccinated, like adolescents and adults, the bacteria may not be detectable for even that long. Since adolescents and adults often do not go to the doctor until late in their illness, there may no longer be any bacteria present. Therefore, choice of test is important:

  • Bacterial culture is the gold standard but it is difficult to perform, takes a long time (up to 2 weeks) and is less likely to be positive later during the disease or  in previously immunized individuals.   It is most sensitive when performed within 2 weeks of cough onset.
  • Pertussis PCR is now widely available, very sensitive and provides results quickly.   Bacteria can be detected even 7 days after taking antibiotics, but false positives can also occur.  PCR tests should NOT be done on anyone without symptoms, even close contacts of confirmed cases.  PCR tests are most sensitive when done within 4 weeks of cough onset.
  • Serology is a test that is performed on blood samples and detects antibodies to pertussis.  This test is usually positive by the time a patient decides to see the doctor about a cough. However, because young infants don’t make antibodies to the protein that the test measures, it is not useful in infants.  In people who were previously immunized, false positives may occur, so doctors need to look at relative levels of antibodies.  This test is most useful in adults and adolescents because testing is usually done too late for culture or PCR tests.  Serology testing can be performed within 2-8 weeks of cough onset.  If the test is done too early in the infection, it may be falsely negative.

Parents who suspect pertussis in themselves or their children should discuss their concerns with their healthcare providers. Providers should be able to help in determining the best approach for making a diagnosis and managing treatment. 

Kristen A. Feemster, MD MPH MSHP
Assistant Professor of Pediatrics
Pereleman School of Medicine at the University of Pennsylvania
Attending Physician, Division of Infectious Diseases
Physician-Scientist at the Vaccine Education Center
The Children’s Hospital of Philadelphia





The Laboratory Diagnosis of Pertussis in the United States

19 04 2012

(Pertussis outbreaks are occurring in the U.S. and elsewhere, yet many healthcare professionals seem reluctant to test for it. We asked Dr. James D. Cherry to explain when testing should be done and we extend our thanks to him for this post on diagnosing whooping cough. Dr. Cherry is a member of the Global Pertussis Initiative (GPI) and author of previous papers on pertussis Dx. Please feel free to share this post with your healthcare provider.)

BACKGROUND:

In pertussis the site of infections is on ciliated epithelial cells in the nasopharynx (NP).  In primary infections (infants and young child not previously vaccinated) the bacterial load is high and is present in the nasopharynx from the onset of illness (coryza) the second week of the paroxysmal stage and often longer.  In children who are vaccine failures the bacterial load in the NP is less than in primary infections and the bacteria are present for a shorter period of time (ie onset of coryza through the second week of cough).

In adults (all of whom have had previous infections unknown to them) the bacterial load is less than in previously vaccinated children and the duration of presence of bacteria is also less.  Also, adolescents and adults rarely seek care for their pertussis cough illness until the third or fourth week from illness onset.  Nevertheless adults with unrecognized pertussis are the most common source of infection in infants who are unimmunized or only partially immunized.

LABORATORY:

Culture:

Culture is 100% specific whereas all other tests are not.  Culture in children is a much more sensitive test than generally believed.  However, today in the U.S., for the most part, culture is a lost art in most diagnostic laboratories because of lack of fresh media and technicians with little experience.  With a good laboratory the main reason for failure to isolate Bordetella pertussis is that the specimen was not collected properly or that it was collected too late in the illness.

To obtain an adequate sample the ciliated cells in the NP must be touched by the dacron tip of the NP swab or the catheter used in a NP aspirate must touch the ciliated cells.  Nasal wash is frequently done but this is much less sensitive than either NP swab or NP aspirate.  For PCR the same facts apply regarding specimen collection.

PCR:

For children (during the first 3 weeks of illness) and adults (during the first week of illness) PCR is the method of choice because it is much more sensitive than culture.  Unfortunately, there has been much misinformation disseminated about PCR results.  PCR is readily available in the U.S. in hospital labs and several commercial labs.

The test that is universally available in the U.S. uses primers that identify insertion sequence (IS) 481 for B. pertussis and IS1001 for B. parapertussis.  Because B. pertussis contains ~238 copies of IS481 this test is exceedingly sensitive.  It is so sensitive that it can pick up examination room contamination because of a previous patient with pertussis or the immunization with DTaP of a previous patient in the room.  Therefore NP specimens should not be collected in rooms where DTaP immunization is being carried out or in rooms that have been occupied by previous patients with pertussis.

Today in the U.S. real time PCR is the method most often used and the number of cycles necessary to obtain a positive result reflects the concentration of B. pertussis in the sample.  The lower the cycle the greater the number of bacteria.  With high cycle detection the possibility of contamination at the collection site is a likely possibility.  However positives are positives regardless of the cycle.  It has been suggested that labs not report high cycle positives as positive results.  This is wrong; these results represent infections or contamination and the physician who obtained the specimen must decide if the findings are consistent with the patient’s illness.  The lab should not call high cycle positives as negative or indeterminate because this relays false information to the physician.

In situations in which both IS481 and IS1001 are positive this may be due to infection with B. holmesii (also a cause of clinical pertussis) or a mixed infection with B. pertussis and B. parapertussis.

PCR should only be performed on patients with cough illnesses.  During pertussis outbreaks asymptomatic infections are very common in previous vaccinees so that you will get positive PCR results from people who are well and these results just confuse the picture (except in planned surveillance studies).

Serology:

All persons who have been previously vaccinated or who have had previous infection will have a rapid rise in antibody to various B. pertussis antigens so that pertussis illness can be diagnosed by single serum serology.  The most useful antibody to determine if a cough illness is pertussis is that to pertussis toxin (PT) because this antigen is exclusive of B. pertussis.  Some tests also determine antibody to filamentous hemagglutinin (FHA) but since this antigen is not exclusive to B. pertussis high titers could be due to B. pertussis infection, other Bordetella spp and M. pneumoniae and perhaps other microorganisms.

Single serum serologic Dx has been used successfully in Massachusetts for over 20 years.  Commercial laboratories also perform single serum serology but unfortunately many of these tests are poor.  Specifically any test that uses the whole B. pertussis bacterium is virtually useless as are tests that don’t express results in units.  Tests that say they are measuring IgM antibody are also useless.  To my knowledge the only commercial test available in the U.S. that is acceptable is that offered by Focus Laboratories.  This test has specificity of ~95%.

Serologic diagnosis will be affected by recent immunization with either DTaP and Tdap so it should not be attempted if the patient has been vaccinated within the previous year.  In general single serum serology should be used for the diagnosis of pertussis in adolescents and adults who have not been recently vaccinated.

White Blood Cell (WBC) Count

Primary infections of pertussis universally have high WBC counts with absolute lymphocytosis.  This is seen in all infants who have not been immunized and who have not received antibody to PT from the mother transplacentally.  Therefore in young infants with afebrile cough illnesses the WBC count with differential can be diagnostic.  Because the WBC count has prognostic implications it should be performed on all infants who might have pertussis at the time of first physician encounter.  A WBC count of  > 20,000 cells/mm3 with a lymphocyte count of  > 10,000 cells/mm3 should be diagnosed as pertussis and immediately treated with azithromycin.

SUMMARY POINTS

  • The onset of cough illnesses in afebrile or minimal febrile persons of all ages should be suspected of having pertussis.
  • Lab confirmation tests should be performed and specific tests employed relate to patient age, vaccine history and duration of cough.
  • For infants and children PCR is the most sensitive and specific test.
  • Whenever possible cultures should also be performed so that epidemic trends can be followed (ie antibiotic resistance, genetic changes in the organism)
  • For adolescents and adults single serum serology to determine antibody to PT is the most sensitive and specific test (unless the patient is seen during the first week of cough).
  • For young infants the WBC count with differential is often diagnostic.

James D. Cherry, MD, MSc

Distinguished Professor of Pediatrics

David Geffen School of Medicine at UCLA

Attending Physician

Pediatric Infectious Diseases

Mattel Children’s Hospital UCLA





My Son Battles Pertussis

30 07 2010

(Our thanks to mom and guest blogger Aleshya Garner.)

My name is Aleshya Garner. My now 10 month-old son, Peyton, is a pertussis survivor. At only 6 weeks of age he developed the disease pertussis, also known as whooping cough.

This disease caused my son to have severe coughing attacks, followed by the struggle to catch his breath, which caused him to turn purple due to low oxygen levels. During each attack, I listened to my son make these awful high-pitched noises, a sound that’s very common in pertussis. As a new mother, the first sounds I expected to hear from my son were soft coos and giggles, not the sounds of him gasping for air. I worried with every cough, “Will he catch his breath?” The only thing you can do is help him through it, with a calm tone, “please breathe Peyton, please breathe” while watching him turn purple.

We are not sure how Peyton got whooping cough, but it could have been prevented had our family been more aware that adults as well as children need booster shots. Just one simple Tdap shot could have possibly prevented Peyton and our family from experiencing this horrible disease.

Not only were we uneducated about pertussis, it took three trips to the ER for the doctors to finally admit Peyton into the ICU at our local hospital. During one of the trips, the doctor told us Peyton’s condition was caused by being constipated, so we were sent home. After being told many wrong diagnoses, they finally ran a pertussis test on my son. The test took about five days to culture. My husband and I were told for five days, by many different doctors, that there was no way our son had pertussis, even though Peyton’s pediatrician suspected it. They were sure it was the flu. The pertussis test came back positive.

I was told that because the hospital staff did not take proper precautions with Peyton’s “possible” pertussis, everyone in every department that he came in contact with was required to take antibiotics, after the pertussis was confirmed.

Peyton was discharged from the hospital after seven days on October 25th. At that time, we were only two weeks into his pertussis. This is surprising, given that resources I read say this disease can last up to ten weeks. Each day was a little bit better, as his attacks were not as frequent as they were in the beginning, but they were just as severe.

More and more cases of pertussis appear each day. A disease that we once just about wiped out is back. As a new mother, I thought “All I have to do is keep him safe from the flu…….” Boy was I wrong. Not in my wildest dreams did I think that my healthy infant son would have to battle with such a potentially fatal disease.

Why isn’t there more awareness out there about pertussis? Why aren’t we encouraged more to follow up on our booster shots to prevent another pertussis outbreak, to protect more babies like Peyton, and to save lives?

To all new parents, grandparents, aunts or uncles, please from the bottom of my heart, get your booster shots. It is that important, and since there is little awareness, help spread the word about pertussis. You may never know it, but it could save a baby’s life.





Whooping Cough: California’s Preventable Epidemic

30 06 2010

Recent news reports warn that California stands to “…suffer the most illnesses and deaths due to pertussis, also known as whooping cough, in 50 years.”  At least 5 infants have died of whooping cough with another 600 suspected cases currently under investigation.  Public health officials have labeled it an epidemic.

It’s easy to forget that before the vaccine was made available, pertussis killed thousands of people and infected hundreds of thousands each year.  Once a vaccine was developed, cases dropped by 99 percent, but the numbers haven’t stayed that low. In 2008, there were more than 13,000 infections and several deaths.

It is estimated that a rising number of families in California are choosing to avoid vaccinating their children through the use of a “personal belief exemption.”  Given this trend, it’s no surprise that we’re seeing a resurgence in infectious diseases like pertussis.

Some basic facts about pertussis:

  1. Whooping cough is a highly contagious bacterial disease that infects the respiratory system.  Symptoms can appear mild at first, including a runny nose and a mild cough. When in doubt, take your child to the doctor right away.
  2. Infants can become gravely ill very quickly.
  3. Symptoms may progress to rapid coughing (sounds like a “whoop” in young children) coupled with difficulty breathing. Infants can turn blue from lack of oxygen.
  4. Left untreated, pertussis can lead to bacterial pneumonia and, especially in infants, seizure, encephalopathy, or death.

How to protect your child from pertussis

  1. The best way to protect infants from pertussis  is to vaccinate them according to the recommended schedule.
  2. Immunity from pertussis begins to fade by the time we reach our teens, so it’s critical that adolescents and adults get the one-time pertussis booster in order to cocoon the infants and others in their lives who are not able to be fully vaccinated.
  3. Keep anyone with a cough away from your child.
  4. Wash your hands and your child’s hands regularly.

Protect your children by talking to your provider to see what vaccines are right for your family. To read more about pertussis, go here.

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