Vaccines

Understanding the Disease

Pertussis is a bacterial infection caused by Bordetella pertussis. The germ is spread when infected people cough or sneeze.

Children with pertussis have decreased ability to cough up respiratory secretions and develop thick, glue-like mucus in the windpipe. This causes severe coughing spells that make it difficult for them to eat, drink, or breathe. The child may suffer from coughing spells for two to three weeks or longer. Sometimes the child coughs several times before breathing in; when the child finally does breathe in there is often a loud gasp or “whooping” sound. The disease is most severe when it occurs early in life; it often requires hospitalization.

The majority of pertussis-related deaths are in young infants which may occur when other bacteria take the opportunity to invade the sick infant’s lungs. Primary pertussis pneumonia also may be life-threatening in infancy. In 1997, adolescents and adults accounted for 46% of reported cases of pertussis, and they are often the ones who spread this disease to infants and children.

Pertussis is one of the most contagious human diseases, so it is a great risk to those who are unvaccinated. Pertussis will develop in 90% of unvaccinated children living with someone with pertussis, and in 50% to 80% of unvaccinated children who attend school or daycare with someone with pertussis. Approximately 50 out of every 10,000 people who develop pertussis die from the disease.

Between 1940-1945, before widespread vaccination, as many as 147,000 cases of pertussis were reported in the United States each year, with approximately 8,000 deaths caused by the disease. In 1976, there were 1,010 case of pertussis in the US, the lowest number of cases ever reported. Over the past few years the number of reported cases of pertussis has increased, reaching 25, 827 in 2004. Worldwide, there are an estimated 300,000 annual deaths due to pertussis.

In 2004, adolescents 11-18 years of age and adults 19-64 years of age accounted for 34% and 27% of the cases of pertussis in the US. The true numbers are probably much higher in these age ranges because pertussis is often not recognized in adults. These cases are very important because teenagers and adults with pertussis can transmit the infection to other people, including infants who are at greatest risk for complications and death. Recommendations for the use of newly licensed vaccines for adolescents and adults have recently been published.

Available Vaccines

No pertussis-only vaccine is available. The pertussis vaccine is available as:

• DTaP (Diphtheria Toxois-Tetanus Toxoid-acellular Pertussis vaccine)
• DTaP in combination with Haemophilus influenzae type b (Hib) vaccine
• DTaP in combination with hepatitis B and inactivated polio vaccines
• DTaP in combination with Hib, hepatitis B and inactivated polio vaccines
• Tdap (Tetanus Toxoid reduced-Diphtheria-acellular Pertussis vaccine)

Vaccines containing the whole cell pertussis component (DTP) are no longer recommended for use in the United States and are not listed here, although they are used in many countries. Vaccines containing lower amounts of diphtheria toxoid—abbreviated with a small d—are utilized in persons 7 years of age or older. Pertussis component-containing vaccines are not available for children 7-9 years of age.

Product Name: Tripedia® (DTaP)
Manufacturer: Sanofi Pasteur
Year licensed: 2001

Product Name: Infanrix® (DTaP)
Manufacturer: GlaxoSmithKline
Year licensed: 1997

Product Name: TriHIBit® (DTaP and Hib conjugate vaccine)
Manufacturer: Sanofi Pasteur
Year licensed: 2001

Product Name: DAPTACEL^TM (DTaP)
Manufacturer: Sanofi Pasteur
Year Licensed: 2002

Product Name: Pediarix^TM (DTaP, hepatitis B, and inactivated polio vaccines)
Manufacturer: GlaxoSmithKline
Year licensed: 2002

Product Name: BOOSTRIX^TM (Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine, Adsorbed for use in 10-18 year old persons) (Tdap)
Manufacturer: GlaxoSmithKline Biologicals
Year licensed: 2005

Product Name: ADACEL^TM (Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertusis Vaccine, Adsorbed for use in 11-64 year old persons) (Tdap)
Manufacturer: Sanofi Pasteur
Year licensed: 2005

Product Name: Pentacel ^TM (DTap, Hib conjugate, hepatitis B, and inactivated polio vaccines)
Manufacturer: Sanofi Pasteur
Year licensed: 2008

None of the pertussis-containing vaccines used in the United states contain thimerosal preservative. For information on the thimerosal content in these vaccines, see the Food and Drug Administration at www.fda.gov/cber/vaccine/thimerosal.htm#t3

History of the Vaccine

In the mid-1940s, the whole cell pertussis vaccine was combined with vaccines against tetanus and diphtheria. The combined DTP vaccine soon was routinely used in the United States, but is no longer recommended.

In 1991, the Food and Drug Administration licensed the DTaP vaccine (diphtheria-tetanus-acellular pertussis). While DTP was made using whole cells of the pertussis germ, DTaP is made using only small, purified snippets of the germs. Fewer side effects have been reported with DTaP than with DTP. In 1991, DTaP was licensed for only the fourth and fifth doses in the series, and in 1997 it was licensed for all five doses.

Two new vaccines were licensed by the Food and Drug Administration for use in adolescents and adults in 2005. These vaccines are abbreviated Tdap.

There are 3 licensed vaccines that combine DTaP with other vaccine components, permitting a reduction in injections.

Who Should and Should Not Receive the Vaccine

Who should receive the vaccine?

• Most infants and children younger than seven years of age should receive DTaP beginning at two months of age.
• 11-18 year olds should receive a single dose of Tdap instead of a Td booster if they have completed the recommended childhood DTP/DTaP immunization series and have not received Td or Tdap. The preferred age for Tdap vaccination is 11-12 years. If they have already received a Td booster, it is recommended that there be an interval of at least 2 years before Tdap is administered to reduce the likelihood of local and systemic reactions. Detailed recommendations for the use of Tdap for preteens and adolescents are available from the CDC.
• Adults 19-64 years of age should also receive a single dose of Tdap to replace a single dose of Td for booster immunization if their most recent tetanus toxoid-containing vaccine was 10 or more years earlier. Tdap may be given at an interval shorter than 10 years since the last tetanus toxoid-containing vaccine in order to protect against pertussis, especially for:
  • Women <65 years of age who are planning to become pregnant.
  • Adults <65 years of age who have or anticipate having close contact with an infant aged <12 months should receive a single dose of Tdap and trivalent inactivated influenza vaccine. Ideally the vaccines should be given at least 2 weeks before contact.
  • Health-care personnel who have direct patient contact should receive a single dose of Tdap.

Detailed recommendations for the use of Tdap in adults are available from the CDC.

Who should not receive the vaccine?

• Those with a history of a serious allergic reaction (such as anaphylaxis) to any of the vaccine components.
• Those with a history of encephalopathy (e.g. coma or prolonged seizures) not attributable to an identifiable cause within 7 days of administration of a vaccine with pertussis components.
• Pertussis vaccines (including the DTaP and Tdap vaccines) are not currently recommended for children who are 7-9 years of age.
• Tdap is not recommended to be administered within 2 years after the most recent tetanus toxoid-containing vaccine.

People with the following conditions should discuss with their health care professional whether they should receive DTaP vaccine:

• Moderate or serious reaction after receiving DTP or DTaP in the past
• Seizure or have a parent or sibling who has had a seizure
• Brain problem that is unstable or getting worse
• People who are moderately or severely ill should consult with their physician before receiving any vaccine.

This vaccine is recommended by:

• Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention
• American Academy of Pediatrics
• American Academy of Family Physicians

The complete childhood immunization schedule can be found at:
http://www.cdc.gov/vaccines/recs/schedules/child-schedule.htm

Dose Schedule

A DTaP vaccine is given to most children at two, four, and six months of age. A fourth dose of DTaP is given between 15 and 18 months, and a fifth dose is given at age four to six years. Pediarix^TM[fn]NNii uses vaccine trade names only for clarity in our presentation of immunization recommendations. NNii does not recommend specific vaccine brands over others.[/fn] can only be given for the first three doses a child receives. TriHIBit® is only licensed for use as a booster dose for children 15-18 months of age. Pentacel^TM is not licensed for use in children over 4 years of age.

If the fourth dose was given after age four years, then no fifth dose is needed.

Receiving combination vaccines from different manufacturers, which may include different component vaccines, can make the dose schedule more complex. However, since giving combination vaccines means fewer shots overall for a child, healthcare providers will usually choose to administer them. Healthcare professionals should attempt to select vaccines for their patients, especially children who have been seen by others, based on what they have already been given.

Children younger than age seven who should not receive the pertussis vaccine should receive the DT (diphtheria-tetanus) vaccine. Between the ages of seven and nine, Td (tetanus-diphtheria), which contains the same amount of tetanus vaccine as in DTaP or DT, but contains much less diphtheria toxoid, is given to protect against tetanus and diphtheria.

The Td vaccine is given to unimmunized children age seven to nine years of age instead of DTaP (or any combination vaccine that includes a pertussis component) because there is no pertussis-containing vaccine licensed for this age group. Two doses are given one to two months apart, and a third dose should be given 6 to 12 months after the second dose.

At age 11-12 years, a booster shot of tetanus-diphtheria-acellular pertussis (Tdap) is needed. It should be given no later than 16 years of age. Every 10 years thereafter, a booster of Td is needed to maintain protection against diphtheria and tetanus.

One booster dose of Tdap is recommended for adults to replace a Td booster. Every 10 years thereafter, a booster of Td is needed to maintain protection against diphtheria and tetanus.

Effectiveness of the Vaccine

The DTaP vaccine is 95% effective in preventing all three diseases that it immunizes against—diphtheria, tetanus and pertussis. It is 59-89% effective in preventing pertussis, while the protection rates for diphtheria and tetanus are higher. Pertussis occasionally occurs in children who have received the pertussis immunization, but it is less severe and has fewer complications.

Known Side Effects

The DTP vaccine is no longer recommended in the United States. DTaP is now recommended because the rates of all reactions following the DTaP vaccine are lower than with DTP; however, if a person had a serious adverse reaction related to DTP, they should not be given DTaP.

Vaccines, particularly pertussis-containing vaccines have been incorrectly blamed for many things in the past. For example, the evidence does not support a casual role for DTaP vaccines as a cause of asthma, autism, type 1 diabetes, brain damage, or sudden infant death syndrome (SIDS). Severe encephalopathy (brain injury) within 7 days after DTaP vaccination is usually explainable by another cause but is also considered a reason to omit the pertussis component in subsequent doses of vaccine.

Half of those vaccinated with DTaP will experience no side effects at all. About half of those vaccinated will experience mild reactions such as soreness where the shot was given, fever, fussiness, reduced appetite, tiredness, or vomiting. Some children may experience a temporary swelling of the entire arm or leg where DTaP was given; this reaction is more common after the fourth or fifth dose of DTaP but does not indicate that it will happen again after the next dose.

Although a single case of recurrent Guillain-Barre syndrome (GBS) after multiple doses of tetanus toxoid has been documented, analyses of cases of GBS found by active surveillance found no increased risk of GBS within 6 weeks following immunizations with tetanus toxoid-containing vaccines.

The rate of severe allergic reactions after DTaP is unknown but these occurred rarely after DTP vaccine so they are theoretically possible.

In rare cases (about 100 children out of 10,000 shots given, or about 1%) children have moderate reactions such as prolonged crying, fever of 105 degrees or higher, seizure, or the child becoming limp, pale, and less alert. Children who have had these reactions after DTaP have had no sequelae.

Studies have shown that children who receive the Hib vaccine in combination with or at the same time as the DTaP vaccine are no more likely to experience side effects than children who only receive the DTaP vaccine.

Related Issues

Outbreaks of pertussis have occurred when immunization levels fall following misinformation claims about pertussis-containing vaccines. To read more about this see Do Vaccines Cause That?! A Guide for Evaluating Vaccine Safety Concerns.

Key References and Sources of Additional Information

• American Academy of Pediatrics, Committee on Infectious Diseases. (2006). Red Book: Report of the Committee on Infectious Diseases (27th ed.). Elk Grove Village, IL..
• Centers for Disease Control and Prevention (CDC). Vaccine Information Statements (VIS).
• CDC. (1997). Pertussis vaccination: Use of acellular pertussis vaccines among infants and young children: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 46(RR-7),1-25.
• CDC. (2000). Use of diphtheria toxoid-tetanus toxoid-acellular pertussis vaccine as afive-dose series: Supplemental recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 49 (RR-#13).
• CDC (2006). Preventing tetanus, diphtheria, and pertussis among adolescents: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, 55(No. RR-3).
• CDC (2006). Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine: recommendations of the Advisory Committee on Immunization Practices (ACIP) and recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for use of Tdap among health-care personnel. MMWR 55(RR-#17).
• CDC. (2008). Licensure of a diphtheria and tetanus toxoids and acellular pertussis adsorbed, inactivated poliovirus, and Haemophilus b conjugate vaccine and guidance for use in infants and children. MMWR 57(39); 1079-80.
• CDC. (2008). Recommended immunization schedules.
  • For infants and children: http://www.cdc.gov/vaccines/recs/schedules/child-schedule.htm.
  • For preteens and adolescents: http://www.cdc.gov/vaccines/recs/schedules/child-schedule.htm
  • For adults: http://www.cdc.gov/vaccines/recs/schedules/adult-schedule.htm

CDC Information

http://www.cdc.gov/nip/publications/VIS/vis-dtp.pdf