Yes. Adolescents or adults who have a history of pertussis disease generally should receive Tdap according to the routine recommendation. This practice is recommended because the duration of protection induced by pertussis disease is unknown (waning might begin as early as 7 years after infection) and because diagnosis of pertussis can be difficult to confirm. Administering pertussis vaccine to people with a history of pertussis presents no theoretical risk. For details, visit CDC’s published recommendations on this topic at www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6702a1-H.pdf.
Ask the Experts: Diphtheria
Tdap vaccination status does not change the approach to evaluating postexposure prophylaxis when HCWs are exposed to pertussis. Tdap vaccines have an uncertain role in the prevention of transmission of pertussis and herd protection. Antipertussis antibody levels begin to decline precipitously after the first year following a single Tdap vaccination. Healthcare facilities should follow the post-exposure prophylaxis protocol for pertussis exposure recommended by CDC regardless of a HCW’s vaccination status (see www.cdc.gov/pertussis/pep.html). HCW can either receive postexposure prophylaxis or be carefully monitored for 21 days after pertussis exposure. Health care personnel should be treated with antibiotics at the onset of signs and symptoms of pertussis and excluded from work for the first 5 days while receiving appropriate antibiotics. CDC supports targeting postexposure antibiotic use to people at high risk of developing severe pertussis, as well as people who will have close contact with others at high risk of developing severe pertussis.
Recent Tdap vaccination does not affect PCR testing. PCR tests are used to detect DNA sequences of the Bordetella pertussis bacterium. PCR tests are very sensitive and could give a false positive result for other reasons. For more information on best practices when performing PCR testing for pertussis see www.cdc.gov/pertussis/clinical/diagnostic-testing/diagnosis-pcr-bestpractices.html.
In April 2018, the Advisory Committee on Immunization Practices (ACIP) published a compilation of all previous recommendations for the prevention of pertussis, tetanus, and diphtheria (MMWR 2018;678 [RR-2]:1-31). The document can be accessed on the CDC website at www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6702a1-H.pdf.
In January 2020, ACIP published updated Tdap recommendations, stating that either Td or Tdap may be used in situations where Td only was previously recommended. The document can be accessed on the CDC website at www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6903a5-H.pdf.
All children should receive a series of DTaP at ages 2, 4, and 6 months, with boosters at ages 15–18 months and at 4–6 years. The fourth dose may be given as early as age 12 months if at least 6 months have elapsed since the third dose.
The most current ACIP recommendations for Tdap can be accessed here at www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6903a5-H.pdf.
A listing of the recommendations follows:
- Tdap can be given regardless of the interval since the last Td was given. There is NO need to wait 2–5 years to administer Tdap following a dose of Td.
- Adolescents should receive a single dose of Tdap (instead of Td) at the 11–12-year-old visit.
- Adolescents and adults who have not received a dose of Tdap, or for whom vaccine status is unknown, should receive a single dose of Tdap as soon as feasible. As stated above, Tdap can be administered regardless of interval since the previous Td dose.
- Children age 7–10 years who are not fully immunized against pertussis (i.e., did not complete a series of pertussis-containing vaccine before their seventh birthday) should receive a single dose of Tdap. If needed, they should complete their series with Td or Tdap. If a Tdap dose is administered at age 10 years or older, the Tdap dose may count as the adolescent Tdap dose.
- All healthcare personnel, regardless of age, should receive a single dose of Tdap as soon as feasible if they have not previously received Tdap and regardless of the time since the last dose of Td.
- Pregnant teens and adults should receive Tdap during each pregnancy, preferably between 27- and 36-weeks’ gestation. Mothers who have never received Tdap and who do not receive it during pregnancy should receive it immediately postpartum.
- Tdap may be administered in any situations where Td only was previously recommended.
- After receiving an initial dose of Tdap, either Tdap or Td can be used to fulfill the decennial (every 10 years) Td booster dose recommendation.
Vaccine efficacy is 80%–85% following 3 doses of DTaP vaccine. Efficacy data following just 1 or 2 doses are lacking but are likely lower. The most effective way to prevent pertussis in early infancy is to vaccinate the mother between 27 and 36 weeks’ gestation. Antipertussis antibodies generated by the mother’s immune system are passed across the placenta to the fetus. One dose of Tdap should be administered during each pregnancy, preferably between 27 and 36 weeks’ gestation. Available data suggest that vaccinating closer to 27 weeks will maximize passive antibody transfer to the infant. A CDC evaluation found Tdap vaccination during the third trimester of pregnancy prevents 78% of pertussis cases in infants younger than 2 months of age and that maternal vaccination reduces the risk of infant hospitalization for pertussis by 90% (www.cdc.gov/pertussis/pregnant/hcp/vaccine-effectiveness.html).
Yes. The January 2020 ACIP updated statement on the use of Tdap (available at www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6903a5-H.pdf) states that a child who receives a dose of Tdap from age 7–9 years as part of the catch-up series (as in this case), should receive another dose of Tdap at age 11 or 12 years.
The first two doses of Td are valid because they are separated by at least 4 weeks. However, the minimum interval between the second and third doses of tetanus-containing vaccine is 6 calendar months. So, the Td component of the Tdap dose is not valid because it was given only 4 months after the second dose. The pertussis component can be counted as valid. The patient should receive another dose of Td or Tdap 6 months after the invalid Tdap dose.
If the first dose of a tetanus toxoid-containing vaccine is administered before the first birthday, 4 doses are necessary before beginning the 10-year cycle of booster doses. If the first dose is administered after the first birthday, 3 doses are necessary. The final dose should be spaced 6 months from the previous dose.
As of January 2020, ACIP recommends that Td or Tdap may be administered in any situation when only Td vaccine was previously recommended. Someone who received a dose of Tdap at age 11 or 12 years should receive a booster dose of Td or Tdap vaccine ten years later, unless tetanus prophylaxis is required sooner due to an injury or if Tdap vaccination is needed during pregnancy.
Yes. Sometimes ACIP makes recommendations that differ from the FDA-approved package insert indications, and this is one of those instances. ACIP recommendations represent the standard of care for vaccination practice in the United States.
A history of tetanus disease is not a reason to avoid tetanus-containing vaccines. Tetanus disease does not produce immunity because of the very small amount of toxin required to produce illness. As long as your patient has no other contraindications, she should receive Tdap now. If she has no documentation of prior tetanus vaccination, she should receive a complete 3-dose primary series (dose #1 of Tdap, followed by dose #2 of Td or Tdap 4–8 weeks later, and dose #3 of Td or Tdap 6–12 months after dose #2).
No. Tdap should be administered as soon as possible.
If Tdap is administered earlier in pregnancy, it should not be repeated between 27 and 36 weeks’ gestation; only one dose is recommended during each pregnancy.
There are two basic products that can be used in children younger than age 7 years (DTaP and DT) and two that can be used in older children and adults (Td and Tdap). Some people get confused between DTaP and Tdap and others get confused between DT and Td. Here’s a hint to help you remember. The pediatric formulations usually have 3–5 times as much of the diphtheria component than what is in the adult formulation. This is indicated by an upper-case “D” for the pediatric formulation (i.e., DTaP, DT) and a lower case “d” for the adult formulation (Tdap, Td). The amount of tetanus toxoid in each of the products is equivalent, so it remains an upper-case “T.”
There are two different DTaP products currently used in the U.S. for the primary series for children ages 2 months through 6 years (Daptacel [Sanofi] and Infanrix [GSK]). ACIP has recommended that, whenever feasible, healthcare providers should use the same brand of DTaP vaccine for all doses in the vaccination series. If vaccination providers do not know or have available the type of DTaP vaccine previously administered to a child, any DTaP vaccine may be used to continue or complete the series. For vaccines in general, vaccination should not be deferred because the brand used for previous doses is not available or is unknown (see the ACIP’s General Best Practices Guidance for Immunization at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html).
If the DTaP brand used for previous doses is not known or not in stock, use whatever DTaP vaccine you have available for all subsequent doses.
If Tdap was inadvertently administered to a child under age 7 years, it should not be counted as either the first, second, or third dose of DTaP. The dose should be repeated with DTaP. Continue vaccinating on schedule. If the dose of Tdap was administered for the fourth or fifth DTaP dose, the Tdap dose can be counted as valid. Please remind your staff to always check the vaccine vial at least 3 times before administering any vaccine.
Yes. In this situation, a second dose of Tdap should be administered at the recommended age of 11 or 12 years.