DTP vaccine may be distinguished as "DTwP" and "DTaP", with "wP" referring to "whole cell pertussis" and "aP" referring to "acellular pertussis". (The acellular form is considered safer and contains far fewer antigens than the older preparation.) Current versions of DTP in Europe do not contain preservatives; older ones contained Thiomersal. In the Netherlands, DTP refers to a mixture of diphtheria, tetanus and poliomyelitis vaccines.
Severe problems closely following DPT immunization happen very rarely. These include a serious allergic reaction, prolonged seizures, a decrease in consciousness, lasting brain disease, or even death. Such severe neurologic events occur after approximately 1 in 140,000 doses of the DPT vaccine (0.0007%). Most of the reactions to DPT injection are thought to be from the pertussis component.
In 1994, the Institute of Medicine of the US National Academy of Sciences published a report stating that if the first symptoms of neurological damage occurred within the first seven days following vaccination with whole-cell pertussis vaccine, the evidence was compatible with the possibility that it could be the cause of permanent brain damage in otherwise apparently healthy children. It continued by stating:
- This serious acute neurologic response to DPT is a rare event. The estimated excess risk ranged from 0 to 10.5 per million immunizations (IOM, 1991). The committee stresses that this is not the strongest statement regarding causality; the evidence does not "establish" or "prove" a causal relation....
- The evidence remains insufficient to indicate the presence or absence of a causal relation between DPT and chronic nervous system dysfunction under any other circumstances. That is, because the NCES is the only systematic study of chronic nervous system dysfunctions after DPT, the committee can only comment on the causal relation between DPT and those chronic nervous system dysfunctions under the conditions studied by the NCES. In particular, it should be noted that the chronic nervous system dysfunctions associated with DPT followed a serious acute neurologic illness that occurred in children within 7 days after receiving DPT.
A safer acellular pertussis vaccine (DTaP) was introduced in the US in 1991; since 2002, whole-cell pertussis vaccines are no longer used in the US.
The usual course of immunisation is five doses between 2 months and 15 years.
Also known by the trademarked name Triple Antigen™.
DTaP is an acronym for the combined diphtheria, tetanus, and acellular pertussis vaccine. The "a" denotes the vaccine's acellular pertussis components, distinguishing it from whole-cell, inactivated DTP (aka DTwP) vaccine. The acellular vaccine uses antigenic fragments of the pertussis pathogen to induce immunity.
The advantage of the acellular vaccine is that it causes substantially fewer side-effects (estimated at 90% fewer), which commonly include local pain and redness, and/or fever. Both DTP and DTaP appear to equally efficacious in generating immunity, but DTaP is universally accepted as safer. Most of the developed world has switched to DTaP, but developing countries continue to use DTP, which is substantially cheaper.
Tdap is the acronym for the collective vaccines preventing tetanus, diphtheria, and pertussis in adolescents and adults that were licensed in the United States in spring of 2005. These vaccines differ from the childhood DTaP vaccines in their indication. The concentration of diphtheria has been reduced in these formulations to prevent adverse reactions. Two Tdap vaccines are available in the U.S. Adacel(R),manufactured by sanofi pasteur, is licensed for use in adults ages 11 to 64. Boostrix(R), manufactured by GlaxoSmithKline, is licensed for use in adolescents ages 10 to 19.
The U.S.'s Advisory Committee on Immunization Practices (ACIP) and Canada's National Advisory Committee on Immunization (NACI) both recommended adolescents and adults receive Tdap in place of their next Td booster (recommend to be given every 10 years).   Tdap can be used as prophylaxis for tetanus wound management. Five years between doses of Td or doses of Td and Tdap is the current standard of care; frequent exposure to tetanus toxoid can cause local reactions. People who will be in contact with young infants are encouraged to get Tdap even if it has been less than 5 years since Td or TT to reduce the risk of infants being exposed to pertussis. The ACIP statement on Tdap use in adolescents encourages 5 years between Td and Tdap to reduce this risk; however, both suggest that shorter intervals may be appropriate in some circumstances, such as for protection in pertussis outbreaks. NACI suggests intervals shorter than 5 years can be used for catch-up programs and other instances where programmatic concerns make 5-year intervals difficult.
- DPT Vaccine and Chronic Nervous System Dysfunction: A New Analysis (1994). Institute of Medicine
- Preventing Tetanus, Diphtheria, and Pertussis Among Adolescents: Use of Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccines, K. R. Broder et al., MMWR Recommendations and Reports, March 24, 2006 / 55(RR03), 1–34, page 18.
- ACIP Votes to Recommend Use of Combined Tetanus, Diphtheria and Pertussis (Tdap) Vaccine for Adults, http://www.cdc.gov/nip/vaccine/tdap/tdap_adult_recs.pdf
- Interval Between Administration of Vaccines Against Diphtheria, Tetanus, and Pertussis http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/05vol31/acs-dcc-8-9/9_e.html
- Price's Textbook of the Practice of Medicine. ISBN 0-19-442344-1
- "Immunisation Against Infectious Disease". (1996). - The Green Book. (with updates) Department of Health (United Kingdom).