Adverese Effects/Contraindications

• Affects ∼ 1/3

• Usually begin within the first 48–72 hours after administration and last 1–2 days

• Symptoms

  • Local swelling, redness, and pain at the injection site

  • Low-grade fever

  • Headaches

  • Fatigue

  • Flu-like symptoms

• Live attenuated vaccine: can cause mild form of the disease, usually appearing within 1–3 weeks of administration : usually caused by replication of the attenuated vaccine strain

• Cardiovascular complications: observed in young men who received mRNA vaccines (COVID-19 vaccines) [19]

  • Pericarditis

  • Myocarditis

  • Myocardial ischemia

• Serious allergic reaction (generally < 1 per million doses)

• Live attenuated vaccine: attenuated course of the disease following immunization (e.g., vaccine-related measles)

• Vaccine injury (∼ 1/1,000,000): permanent injury from a vaccination or a vaccine-related complication (e.g., encephalopathy, seizures, brachial neuritis)

• A precaution is a condition in the recipient that might increase the risk for serious adverse reactions or interfere with a vaccine's ability to produce immunity.

• Generally, vaccination should be deferred when a precaution is present, except when the benefits of protection outweigh the risks.

• Acute moderate or severe illness (with or without fever)

• Rotavirus vaccine: uncorrected GI tract malformation (e.g., Meckel's diverticulum)

• Egg protein-containing vaccines: allergic reactions other than urticaria (e.g., angioedema, bronchospasm) to egg products

• Pertussis vaccine: progressive or unstable neurologic disorders (e.g., uncontrolled epilepsy, infantile spasms, progressive encephalopathy) [22]

• Tetanus toxoid-containing vaccines

  • Development of Guillain-Barré syndrome within 6 weeks of a previous dose

  • Arthus reaction after a previous dose

• Vaccines are generally contraindicated in recipients with conditions that increase the risk for severe vaccine reactions or in whom the vaccine may exacerbate the condition.

• Previous severe adverse reactions (e.g., anaphylaxis)

• Severe adverse reactions to a vaccine component (e.g., egg protein in yellow fever vaccine, yeast in hepatitis B vaccine)

• Rotavirus vaccine

  • Severe combined immunodeficiency (SCID)

  • History of intussusception [24]

• Pertussis vaccines: risk of encephalopathy (e.g., prolonged seizures, decreased level of consciousness, coma) within 7 days following a previous dose

• Live, attenuated virus vaccinations [22]

  • Pregnant individuals

  • Immunodeficient individuals (e.g., individuals receiving chemotherapy or long-term immunosuppressive therapy, individuals with congenital immunodeficiencies, patients with HIV and severe immunocompromise)

  • Individuals receiving IVIG therapy (e.g., for Kawasaki disease)

• Fever within 48 hours

• Current or recent mild illness (e.g., rhinorrhea, otitis media, mild diarrhea)

• Current or recent antibiotic therapy (exception is oral live typhoid vaccine )

• Current or recent low-dose and/or short-term steroid use (i.e., < 2 mg/kg/day or < 20 mg/day, < 14 days)

• Previous mild or moderate localized cutaneous reaction (e.g., swelling, redness, soreness) following any vaccination

• Preterm infants

  • Should be immunized according to chronological age, not gestational age

  • The exception is the hepatitis B vaccine: vaccination should be delayed by a month or until hospital discharge for infants weighing < 2 kg born to HBsAg-negative mothers.

  • Adjustment according to weight: no dose adjustment is needed

Immunocompromised individuals should generally not receive live attenuated vaccines.

• Efficacy of immunization is reduced in HIV-infected individuals (due to impaired immune function)

• The immunization schedule should be observed with the following exceptions:

  • Live-attenuated varicella zoster and MMR vaccine should not be given if the CD4 count is < 200 cells/mm3 (CD4 percentage < 15% in patients ≤ 5 years) or if the patient has AIDS-defining conditions.

  • Live-attenuated influenza vaccine is not recommended, regardless of the CD4 count; inactivated influenza vaccine should be given instead.

  • The inactivated polio vaccine should be used instead of the live-attenuated polio vaccine.

• Immunizations that are not part of the standard immunization schedule:

  • Inactivated vaccines are generally safe

  • Live vaccines should generally not be given to severely immunocompromised patients