Tdap vaccine

The tetanus, diphtheria and acellular pertussis (Tdap) vaccine is a prescription medication in the vaccine class.

The Tdap vaccine is approved to prevent tetanus, diphtheria, and acellular pertussis infections. It is a safe and effective vaccination that helps fight against these infectious diseases and related complications.

It is administered for adolescents aged 11-12 and then as a booster for adults every 10 years. It is not a part of routine national immunization programs.

The Tdap vaccination does not go through normal drug-like processes, including absorption, distribution, metabolism, or excretion. Instead, it stimulates the immune system to produce defence immunity.

The common side effects of the Tdap vaccine may include pain, redness, or swelling at the injection site, mild fever, headache, tiredness, nausea, vomiting, diarrhoea or stomach ache.

Tdap vaccines are available as a liquid suspension for injection.

Tdap vaccines are available in many countries like the United States, Canada, United Kingdom, Australia, and various European, Asian, South American, and African nations.

Tdap vaccination comprises three components to protect against tetanus, diphtheria, and pertussis (whooping cough).

Tetanus Toxoid: The vaccine contains an inactivated variant of the tetanus toxin produced by the bacteria called Clostridium tetani. This inactive toxin activates the immune system without causing the disease.

Toxoid Diphtheria: The vaccine contains an inactivated variant of the diphtheria-causing bacteria Corynebacterium diphtheriae's toxin. The immune system is induced to produce antibodies in response to the inactivated toxin.

Pertussis: The vaccine contains various proteins from the bacteria Bordetella pertussis, which causes whooping cough. These proteins are either inactivated or produced by bacteria that have been genetically engineered. They stimulate the immune system to produce anti-pertussis antibodies.

Tdap triggers the immune system to recognize and respond to these three bacterial threats. If a person is later exposed to tetanus, diphtheria, or pertussis, their immune system may rapidly produce antibodies to kill the germs, protecting them against these diseases.

The Tdap vaccine is available in the form of suspension for injection. It is typically provided in vials or pre-filled syringes.

Suspension for injection: To be administered parenterally, as applicable.

• To protect against tetanus, a bacterial infection can occur due to wounds or trauma.
• It protects against diphtheria, a potentially fatal infectious respiratory infection.
• The vaccine also protects against pertussis (whooping cough), a highly contagious disease important for newborns and young children.

Tdap Vaccine can help support various health benefits:

• Tetanus Prevention: The Tdap vaccine provides critical protection against the pathogen Clostridium tetani, which causes tetanus. Tetanus spores can enter the body through wounds, burns, or injuries and are found in soil. Exposure to these spores can cause severe muscle stiffness and spasms without vaccination, potentially leading to death or life-threatening complications.

• Diphtheria Protection: Tdap immunization protects against diphtheria, a bacterial infection caused by Corynebacterium diphtheriae. This condition predominantly affects the respiratory system, resulting in symptoms such as a soreness of throat, fever, and difficulty breathing. Diphtheria can cause serious problems, including heart and nerve damage, if not treated promptly.

• Pertussis Prevention: The vaccine effectively prevents pertussis, also known as whooping cough. The bacteria Bordetella pertussis causes this highly contagious respiratory infection. Pertussis can cause intense coughing fits, which can cause breathing issues. It is especially harmful for newborns and young children, who are more susceptible to its effects.

• Booster: For individuals who received the childhood DTP (diphtheria, tetanus, and pertussis) series, the Tdap vaccine acts as a booster. This helps maintain and boost a person's immunity to certain diseases, assuring sustained protection throughout adolescence and adulthood.

• Herd Immunity: Tdap promotes herd immunity through widespread vaccination. This means that most of the population is immune to the diseases, making it more difficult for viruses to spread. This protects people who may be more vulnerable, such as newborns who are too young to receive the complete vaccine series.

• Community Health Impact: The Tdap vaccine significantly reduces transmission of tetanus, diphtheria, and pertussis throughout communities. This benefits public health by lowering the prevalence of specific disorders and associated healthcare costs.

Tdap vaccine is approved for use in the following clinical indications:

• All adolescents aged 11 or 12 who have not previously received Tdap vaccination should receive a single dose.

• Pregnant women should be administered Tdap at some point during their pregnancy, preferably between 27 and 36 weeks.

• To protect against pertussis, parents, caregivers, and household contacts of infants younger than 12 months, including healthcare staff, should obtain Tdap.

• It is advised that healthcare workers, particularly those with direct patient contact, are advised to take a single dose of Tdap as part of their routine immunization.

• Individuals with wounds or injuries, particularly deep or infected ones who have not gotten a tetanus-containing vaccination in the previous 5 years should be given a Tdap vaccine.

• Tdap may be suggested for travellers, particularly those working in medical settings abroad, depending on specific circumstances.

Parenterally: Tdap vaccine is available as a suspension for injection. It should be shaken thoroughly before use to ensure that it is appropriately suspended and administered by intramuscular injection as a 0.5 mL dose from vial using a sterile needle or syringe in the upper arm's deltoid. This location was used for the injection because it has a large, easily accessible muscle.

It should be administered intramuscularly only and not intravenously, intradermally or subcutaneously.

It can be only given by a healthcare professional in a hospital setting or during routine immunization programs.

After administration, the healthcare provider will document the vaccination, including the date, time, dose, and injection site.

The dosage and duration of treatment should be as per the treating physician's clinical judgment.

Injection for suspension:

(15.5mcg/2Lf/5Lf)/0.5mL (Adacel)

(18.5mcg/2.5Lf/5Lf)/0.5mL (Boostrix)

where,Lf = limits of flocculation; pertussis/diphtheria/tetanus

Dosage Adjustment for Adult Patients

Immunization against Tetanus, Diphtheria, and Pertussis

• Booster immunization (Boostrix) of 0.5 mL intramuscularly for individuals aged more than 10 years

Routine booster vaccination

First dosage: Give within five years after the dose of the DTaP (diphtheria, tetanus, and acellular pertussis) series or after a dose of Td (tetanus and diphtheria toxoids adsorbed).

May administer a second dose nine years after the first Tdap treatment.

• Booster injection (Adacel) of 0.5 mL intramuscularly for individuals aged 10 to 64 years.

Routine booster vaccination

First dosage: Administer the first dose five years or less after the last DTaP or Td dose.

May administer a second dose eight years after the first Tdap treatment.

Management of wounds

Tetanus prophylaxis for wound management may be used.

If more than five years have passed since receiving a previous dose of a vaccination that contains tetanus toxoid, a booster dose may be given.

Tdap vaccine is available as liquid suspension for injection.

The Tdap vaccine should be used to protect against tetanus, diphtheria, and acellular pertussis infections, along with no appropriate dietary restrictions.

When administered, the Tdap vaccine usually has little effect on dietary or food substances. Consuming regular foods and drinks before and after receiving the vaccine is safe.

However, staying fully hydrated and maintaining a balanced and healthy diet to support overall immune system function is always recommended, which can boost the effectiveness of vaccines.

Tdap vaccine may be contraindicated in the following conditions: -

• Anaphylaxis reactions (Hypersensitivity after a previous dose)
• Allergic to latex rubber (pre-filled syringe form)
• Guillain-Barré Syndrome (rarely)
• A history of hypersensitive responses of the Arthus type following a prior dose of tetanus or diphtheria toxoid vaccine; postpone immunization until at least 10 years have elapsed since the last dose of the tetanus-toxoid vaccine.
• Encephalopathy after receiving pertussis antigen seven days earlier
• Children aged 6 months yrs.

The treating physician must closely monitor the patient and keep pharmacovigilance as follows.

• Children with weak immune systems, such as those with HIV/AIDS infection or cancer or who are taking certain drugs, may not respond as well to the Tdap vaccines and may consult a healthcare professional who might suggest modifying the vaccine schedule or giving additional doses to these people to improve protection.
• It may be advisable to postpone the vaccination if the child is currently experiencing a fever, minor infections or a moderate to severe sickness.
• Healthcare professionals should assess the risks and benefits of the vaccination in case of any severe allergic reactions or a severe reaction to a previous dose of the Tdap vaccine to determine whether further immunization is required.
• Administration of an injectable vaccination has been associated with syncope.

Caution is advised when consuming alcohol with the Tdap vaccine

There is no sufficient scientific evidence traceable regarding the use and safety of the Tdap vaccine in the breastfeeding population.

There is no sufficient scientific evidence traceable regarding the use and safety of the Tdap vaccines in concurrent use with any particular food.

The adverse reactions related to Tdap vaccine can be categorized as

• Common: Pain, redness or swelling at the site of injection, headache, headache and fatigue
• Less Common: Body aches/muscle weakness, lymph node swelling and gastrointestinal symptoms like nausea or vomiting.
• Rare: Severe allergic reactions, seizures, syncope (fainting) and Guillain-Barré Syndrome (GBS)

Drug interactions with the Tdap vaccination are usually minimal. It is often regarded as safe to give with the majority of drugs.

The most common clinically relevant drug interactions of the Tdap vaccine are with immunosuppressant drugs like prednisone or cyclosporine, which, when used in very high doses, suppress the immune system and may reduce the effectiveness of the Tdap vaccine.

The common side of the Tdap vaccine includes the following-

• Pain, redness, or swelling at the site where the shot was given
• Nausea
• vomiting
• Headache
• Feeling tired
• Diarrhoea
• Stomach ache
• Mild fever

The Tdap vaccine should be prudent in the following group of special populations.

• Pregnancy: The Tdap (Adacel) vaccine is frequently considered safe during pregnancy. There is little human research, even though studies on animals have demonstrated minimal or no adverse effects on the developing foetus.

Tdap administration during pregnancy, ideally between 27 and 36 weeks, provides the best protection for the mother and the developing baby. Infant protection, at postpartum vaccination, is less effective. After receiving Tdap, protection takes about two weeks to develop, and newborns are still susceptible during this time. Tdap should not be administered before conception, but if it is, it should be repeated throughout the pregnancy. Tdap does not require any further doses between 27 and 36 weeks of pregnancy and can be safely given earlier in pregnancy if needed, such as during wound care or community pertussis epidemics.

• Paediatrics: Tdap vaccine is not recommended for this population.

Dosage Adjustment for Paediatric Patients

There are no specific dosage adjustments provided.

• Geriatrics: The Tdap vaccination is often safe for elderly people. It protects against pertussis, diphtheria, and tetanus. Immunization continues to be effective at avoiding significant consequences even though the immune response might decline with age. In older people, the advantages of immunization in avoiding specific diseases outweigh any potential risks.
• Lactating mothers: There is no sufficient scientific evidence traceable regarding the use and safety of the Tdap vaccine for lactating mother populations.

Dosage adjustment in kidney impairment

There are no specific dosage adjustments provided.

Dosage adjustment in hepatic impairment

There are no specific dosage adjustments provided.

Overdosage of the Tdap vaccines rarely occurs as healthcare professionals administer them according to specific or precise dosing guidelines.

There is no specific antidote or treatment for excessive intake of the Tdap vaccine. Medical attention should be sought immediately when an overdose is suspected, followed by monitoring any adverse effects or allergic reactions. Supportive therapy should also be given, addressing any symptoms that persist or worsen. Physical treatment might be added if necessary.

Pharmacodynamics of Tdap vaccine

The Tdap vaccines have a physiological mechanism that plays a role in their pharmacodynamics.

After injection, the immune system detects these antigens as foreign material and develops an effective defence. As a response, specialized immune cells, known as B cells, produce antibodies that block the toxins associated with diphtheria and tetanus. This antibody production provides immunity against various diseases. Tdap also promotes the development of memory T and B cells, which store a "memory" of the antigens. This produces a long-lasting defence mechanism that can react quickly should the individual eventually come into contact with the pathogens. The pertussis component of the vaccine is also essential because it causes the immune system to initiate a targeted response to the Bordetella pertussis bacteria, which causes whooping cough. This reaction lessens the severity of pertussis and prevents further spread.

Thus, an effective immune reaction is an effective defence against tetanus, diphtheria, and pertussis infections, protecting people from possibly life-threatening and fatal diseases caused by bacteria.

Pharmacokinetics of Tdap vaccine

Evaluation of pharmacokinetic properties is not required for Tdap vaccine.

The length of disease protection is long-lasting (years), although the onset of it is relatively slow.

Duration: Variable, probably longer than 10 years; maternal Tdap pertussis antibodies seem to decline between consecutive pregnancies significantly.

• Jones, C.E., Calvert, A., Southern, J. et al. A phase IV, multi-centre, randomized clinical trial comparing two pertussis-containing vaccines in pregnant women in England and vaccine responses in their infants. BMC Med 19, 138 (2021). https://doi.org/10.1186/s12916-021-02005-5
• Hitt Sharma, K. Anil, Sameer Parekh, Pramod Pujari, Sunil Shewale, R.L. Madhusudhan, Jaya Patel, Anand Eswaraiah, Umesh Shaligram, Sunil Gairola, Harish Rao,
• A phase-I, open label clinical trial to assess the safety of Tdap vaccine manufactured by Serum Institute of India Pvt. Ltd. in adults, Vaccine, Volume 39, Issue 6,2021,Pages 882-885,ISSN 0264-410X,https://doi.org/10.1016/j.vaccine.2020.12.062.

• Inform the caregivers of the Tdap vaccine's schedule and the importance of booster doses to maintain long-term protection.
• Confirm the patient has been informed of the details provided and approve the immunization before proceeding. Obtain their willingness and informed consent based on their awareness of the risks and benefits.
• Assure caregivers that Tdap vaccine immunizations are generally safe, with only minor, short side effects. Encouraging them to immediately report any unexpected or severe responses to the healthcare physician and, whenever applicable, to use reporting systems like the Vaccine Adverse Event Reporting System (VAERS)
• Inform caregivers of the recommended immunization schedule, depending on the vaccine brand. Also, mention the ages at which the doses should be administered and give the Vaccine Information Statements, which must be disclosed before immunization by the National Childhood Vaccine Injury Act of 1986 about the Centres for Disease Control and Prevention (CDC) website (www.cdc.gov/vaccines), these resources are freely accessible.

https://www.ncbi.nlm.nih.gov/books/NBK582551/

https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5037a4.htm

https://www.indianpediatrics.net/oct2014/785 figure1.pdf

https://www.pediatriconcall.com/drugs/drugs-a-to-z/h