DPT vaccine

**DPT** is a class of combination vaccines against three infectious diseases in humans: diphtheria, pertussis (whooping cough), and tetanus. The vaccine components include diphtheria and tetanus toxoids and killed whole cells of the bacterium that causes pertussis. The vaccine also known as "DTP" or "DTwP", whereas the lower-case "w" indicated whole-cell inactivated pertussis.

The usual course of childhood immunization in the United States is five doses between two months and 15 years. For adults, Td boosters are recommended every ten years.

In the late 20th century, vaccinations helped to reduce the incidence of childhood pertussis in the United States. However, due to a downturn in the amount of immunizations received, reported instances of the disease increased 20-fold in the early 21st century, resulting in numerous fatalities. Over this time, many parents declined to vaccinate their children against pertussis for fear of side effects. In 2009, the journal *Pediatrics* concluded the largest risk among unvaccinated children was not the contraction of side effects, but rather the disease that the vaccination aims to protect against.

DTP was licensed in 1949.

## Combination vaccines with acellular pertussis

DTaP and Tdap are both combined vaccines against diphtheria, tetanus, and pertussis. The lower-case "d" and "p" indicate smaller concentrations of diphtheria toxoids and pertussis antigens, and "a" in "ap/aP" indicates that the pertussis toxoids are acellular.

### DTaP

DTaP (also DTPa and TDaP) is a combined vaccine against diphtheria, tetanus, and pertussis, in which the pertussis component is acellular. This is in contrast to whole-cell, inactivated DTP (DTwP). The acellular vaccine uses selected antigens of the pertussis pathogen to induce immunity. Because it uses fewer antigens than the whole-cell vaccines, it is considered to cause fewer side effects, but it is also more expensive. Recent research suggests that the DTP vaccine is more effective than DTaP in conferring immunity, because DTaP's narrower antigen base is less effective against current pathogen strains.

### Tdap

Tdap, (also dTpa), is a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine. It was licensed in the United States for use in adults and adolescents on June 10, 2005. Two Tdap vaccines are available in the US. Adacel, manufactured by Sanofi Pasteur, is licensed for use in adults ages 11 to 64. Boostrix, manufactured by GlaxoSmithKline, is licensed for use in individuals aged 10 and older. In January 2011, the US Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) recommended the use of Tdap in adults of all ages, including those age 65 and above. In October 2011, in an effort to reduce the burden of pertussis in infants, the ACIP recommended that unvaccinated pregnant women receive a dose of Tdap. On October 24, 2012, the ACIP voted to recommend the use of Tdap during every pregnancy.

The ACIP and Canada's National Advisory Committee on Immunization (NACI) recommended that both adolescents and adults receive Tdap in place of their next Td booster (recommended to be given every ten years). Tdap and Td can be used as prophylaxis for tetanus in wound management. People who will be in contact with young infants are encouraged to get Tdap even if it has been less than five years since Td or TT to reduce the risk of infants being exposed to pertussis. NACI suggests intervals shorter than five years can be used for catch-up programs and other instances where programmatic concerns make five-year intervals difficult.

The World Health Organization (WHO) recommends a pentavalent vaccine, combining the DTP vaccine with vaccines against *Haemophilus influenzae* type B and hepatitis B. Evidence on how effective this pentavalent vaccine is compared to the individual vaccines has not yet been determined.

A 2019 study in the *American Economic Journal* found that state requirements mandating the use of the Tdap vaccine "increased Tdap vaccine take-up and reduced pertussis (whooping cough) incidence by about 32 percent."

## In pregnancy

Guidelines on prenatal care in the United States state that if an urgent need for tetanus protection occurs during pregnancy, Td vaccine should be administered. If no urgent need arises and the woman has previously received tetanus vaccine, Td vaccination should be delayed until the postpartum period. All postpartum women who have not received Td or Tdap vaccine in the last two years are recommended to receive Tdap prior to discharge after delivery. Pregnant women who have never received a tetanus vaccine (i.e., have never received DTP, DTaP, or DT as child or Td or TT as an adult) are recommended to receive a series of three Td vaccinations starting during pregnancy to ensure protection against maternal and neonatal tetanus. In such cases, administration of Tdap is recommended after 20 weeks' gestation, and in earlier pregnancy a single dose of Tdap can be substituted for one dose of Td, and then the series completed with Td. The United States' Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP) voted to recommend that health-care personnel should administer a dose of Tdap during each pregnancy at 27 through 36 weeks gestation irrespective of the patient's prior history of receiving Tdap.

## Related vaccines

Also available are the **DT** and **Td** vaccines, which lack the pertussis component.

In the United Kingdom, the Netherlands, and France, the DTP vaccine is combination vaccine against diphtheria, tetanus, and poliomyelitis. In the Netherlands, pertussis is known as *kinkhoest* and DKTP refers to a combination vaccine against diphtheria, kinkhoest, tetanus, and polio.