Trihibit Disease Interactions

Ideally, vaccination should occur when an individual is healthy, thus minimizing the risk of an adverse host reaction and/or vaccine failure. However, a current or recent infection does not necessarily preclude the use of vaccines, depending on the severity of the patient's symptoms and their etiology. Superficial infections and minor acute illnesses such as a mild upper respiratory infection with or without low-grade fever do not contraindicate immunization, particularly if prompt administration of a vaccine is deemed necessary or beneficial. In fact, when vaccines are administered during the course of a minor illness, the risk of adverse events is not increased, and serum antibody response is not often diminished. On the other hand, if fever or symptoms suggest a moderate or severe illness, it is usually appropriate to withhold vaccination until the patient has recovered. In addition to the potential risks already mentioned, evolving signs and symptoms of the illness can sometimes confound the diagnosis of a vaccine reaction if it develops. In the presence of any infection, the decision to administer or withhold/defer immunization should take into consideration the benefits versus the risks to an individual patient.

In patients with thrombocytopenia or coagulation disorders, intramuscular injections may produce bleeding and hematomas. Patients with a platelet count less than 50,000/mm3 are at an increased risk. Caution is advised if the vaccine (e.g., plague vaccine, hepatitis A and B vaccines, and aluminum-adsorbed DTaP, DTP, DT, or Td) must be administered intramuscularly. The risk of bleeding may be minimized by vaccination immediately after the administration of replacement factor, use of a 23-gauge (or smaller) needle, and immediate application of direct pressure to the vaccination site for at least 2 minutes.

The use of whole-cell pertussis vaccine has rarely been associated with the development of severe encephalopathies. Permanent brain damage and death have been reported. Although a causal relationship has not been established, caution is advised when pertussis vaccination is considered in patients with underlying neurologic disorders. The decision to administer or defer vaccination should be made on an individual basis after assessing the potential risks and benefits to the patient. Generally, the presence of a progressive, unstable, or evolving neurological disorder is considered a contraindication or reason to defer, sometimes permanently, vaccination with whole-cell pertussis vaccine. The use of acellular pertussis vaccine under these circumstances has not been evaluated but should probably be avoided as well. Infants and children with a history of seizures may be vaccinated, provided the seizures are well-controlled and not associated with a progressive or degenerative neurologic disorder. However, these patients have an increased risk of post-pertussis vaccination (within 48 hours) seizures and should receive acellular pertussis vaccine, since it is less frequently associated with moderate to high fever and thus, less likely to precipitate a seizure. Prophylactic antipyretic therapy (e.g., acetaminophen) is also recommended for the first 24 hours following vaccination. Patients with stable neurologic conditions, such as developmental delay or cerebral palsy, may receive pertussis vaccination. In any case, if pertussis immunization is withheld during the first year of life, immunization against diphtheria and tetanus may be withheld simultaneously because the risk of acquiring these conditions is low (in developed countries) in children under the age of 1 year who are nonambulatory.

The expected serum antibody responses may not be obtained when vaccines and/or toxoids are administered to patients with primary or acquired immunodeficiency, including those with severe combined immunodeficiency, hypogammaglobulinemia or agammaglobulinemia, HIV infection, altered immune states (due to diseases such as leukemia, lymphoma, or generalized malignancy), or immunosuppression due to drug or other treatments (e.g., corticosteroids, alkylating agents, antimetabolites, or radiation).

The expected antibody responses may not be obtained when live attenuated vaccines and/or toxoids are administered to immunosuppressed persons, including those receiving immunosuppressive therapy. Caution and close monitoring is advised.