Saar Kuzi
Alessandra Coutinho Fernandes
William Cope
Richard Tapping
Kashif Ahmad
Reda Sadki
Shubhra Kanti Karmaker Santu
Adam P Rusch
Elizabeth Edwards
Matthew LawFA16 Immunization Module’s Updates
DTaP, DT, Tdap, and Td – A Brief Overview of the Vaccines Against Diptheria, Tetanus, and Pertussis
I was curious about the distinguishing factors among the various vaccines for diphtheria, tetanus, and pertussis, and looked for further clarification. This update is a brief overview of my findings, and though it does not focus directly on one of the given topics from the list, a few of the topics are incorporated as they pertain to these vaccines. In an effort to keep the update as brief as possible, not all topics could obviously be discussed here.
Diptheria and tetanus are vaccinated against using toxoids. A toxoid is a purified toxin that has been inactivated by formalin treatment. Since the diseases are mediated by the secretion of toxins from Corynebacterium diptheriae and Clostridium tetani, respectively, the vaccines are aimed at creating antibodies against the toxins.[1] Pertussis vaccines can be whole-cell or acellular in nature. Whole-cell vaccines contain an inactivated Bordetella pertussis cell. Acellular vaccines are subunit-based and consist of inactivated pertussis toxin and other antigens of B. pertussis in varying combinations. While whole-cell pertussis vaccines are still used in many countries, they are no longer available in the United States.[2]
The movement from whole-cell to acellular pertussis vaccines in the United States rose due to adverse effects of the whole-cell vaccine. Manufacturing of whole-cell vaccines does not eliminate the presence of the endotoxin and other components of B. pertussis that can lead to fever, irritability, and reactions at the injection site including redness, swelling, and pain.[3]
There are currently four combination vaccines available for the prevention of diphtheria and tetanus: DTaP, DT, Tdap, and Td. Two of the vaccines – DTaP and Tdap – provide protection against pertussis. The strength of the vaccine components is indicated by the use of upper- and lower-case letters in the vaccine abbreviations. Capital letters (D, T, and P) signify full-strength doses, whereas lower-case letters indicate reduced doses. The strength of the doses corresponds with the target age-group of the vaccines (see below). The lower-case “a” present in the abbreviations DTaP and Tdap implies the use of acellular components versus whole-cell as in the DTP vaccine, which is no longer utilized in the US.[4]
DTaP and DT vaccines are administered only to children under the age of 7. DTaP vaccines contain high doses of diphtheria and tetanus toxoids as well as three to five B. pertussis acellular antigens. The vaccine is administered in 5 doses at 2, 4, 6, and 15-18 months and 4-6 years of age. DT vaccines are used in children who have experienced adverse reactions to the pertussis component of the DTaP vaccine.[5]
Tdap vaccines contain reduced amounts of the diphtheria toxoid and pertussis antigens. The vaccine is administered in single doses between 11-18 years of age and then again after the age of 19. In cases where a child over the age of 7 has not received a complete vaccination series against pertussis and has no prior history of adverse reactions to the pertussis vaccine, Tdap is administered following “catch-up” protocol. It is also recommended that pregnant women receive a dose of Tdap between the 27th to 36th weeks of pregnancy to maximize infants’ passive immunity. Td vaccines are used as a booster for tetanus and diptheria in adults and should be obtained every 10 years following Tdap administration.[6]
[1] Parham, Peter. (2009). Chapter 14: Vaccination to prevent infectious diseases (p. 440). The Immune System (3rd ed.). New York: Garland Science
[2] CDC: The Pink Book, Ch. 16 (http://www.cdc.gov/vaccines/pubs/pinkbook/pert.html)
[3] Gabutti, Giovanni, et al. (2015). Pertussis: Current perspectives on epidemiology and prevention. Human Vaccines and Immunotherapeutics, 11(1): 108-117. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4514233/) & CDC: The Pink Book, Ch. 16 (http://www.cdc.gov/vaccines/pubs/pinkbook/pert.html)
[4] CDC: Diptheria Vaccination – What Everyone Should Know (http://www.cdc.gov/vaccines/vpd-vac/diphtheria/public/index.html) & Parham, Peter. (2009). Chapter 14: Vaccination to prevent infectious diseases (p. 440). The Immune System (3rd ed.) New York: Garland Science
[5] CDC: The Pink Book, Ch. 16 (http://www.cdc.gov/vaccines/pubs/pinkbook/pert.html) & CDC: Diptheria Vaccination – What Everyone Should Know (http://www.cdc.gov/vaccines/vpd-vac/diphtheria/public/index.html)
[6] CDC: The Pink Book, Ch. 16 (http://www.cdc.gov/vaccines/pubs/pinkbook/pert.html) & CDC: Diptheria Vaccination – What Everyone Should Know (http://www.cdc.gov/vaccines/vpd-vac/diphtheria/public/index.html)
@ Elizabeth Edwards I think the need for a booster is due more to the latter - the decline in the immune response over time to the toxoids. @ Richard Tapping would be able to provide a better explanation of the events leading to this decline. There is some disagreement in the literature about the necessity for a booster every 10 years, especially in countries of the world with more rigorous vaccination regimens and higher compliance. Some research has suggested that sufficient immunity remains at 10 years and longer window of time is acceptable between boosters in those regions.
@ Eden Perez One of the main factors I think contributing to the transition in the US is the difference in mild and severe adverse reaction frequency between whole-cell and acellular pertussis vaccines. Acellular pertussis vaccines have a lower frequency of both mild and severe adverse reactions. I am sure this is not the only factor that contributed to the transition, though.
The link below is to an information sheet published by WHO I ran across during my research for the update. It summarizes the adverse reactions and frequency with each type of vaccine.
http://www.who.int/vaccine_safety/initiative/tools/DTP_vaccine_rates_information_sheet.pdf
@Gabrielle Kuhn Thank you for breaking down a concepts hat seems so intimidating! I wonder how the technology that is used for the first world manufacturing of these vaccines plays into their safety in comparison to those being produced and administered in the third world. I found it very interesting that this particular vaccine requires a booster every ten years regardless of age. Could it be due to genetic changes that the toxins undergo over time or simply our organisms not being capable of the specific immunologic memory required to maintain efficient immunity? Thanks for sharing.
Thanks for sharing this overview. I have wondered about this too so this information was really helpful to better understand the differences and the components that need to be considered in each vaccine. I find it interesting that whole-cell pertussis vaccines are no longer used in the U.S. anymore, but are still found in other countries.
@Gabrielle Kuhn. You've hit a goldmine here. It is very important to distinguish the different vaccine formulations for these three pathogens, the difference doses and age groups for administration. The microbiology course will also cover this material. THE WHOLE CLASS SHOULD READ THIS. Thank you!