Vaccine Administration and Safety in Infants

Local Reactions

Local reactions to vaccines, such as pain, redness, and swelling at the injection site, occur in a significant proportion of infants, with pain affecting approximately 10-20% of infants, redness affecting up to 10-30%, and swelling occurring in 10-30% of vaccinated infants 1, 2, 3
Local reactions to pneumococcal vaccines occur in approximately 50% of recipients and include pain at the injection site, erythema, swelling, local induration, and occasionally a palpable nodule, typically persisting for less than 48 hours and are generally mild to moderate in severity, according to the CDC 4
Previous pneumococcal vaccination within 2 years is a factor that can contribute to more severe local reactions, according to the CDC 4
To manage local reactions, apply a cool compress to the injection site and continue normal activities as tolerated, as advised by the CDC 5

Systemic side effects, including fever, occur in approximately 10-35% of infants younger than 2 years within 24 hours of vaccination, with fever being the most common adverse reaction to vaccines, according to CDC guidelines 1, 2, 6
Irritability/fussiness is common after DTaP-containing vaccines, and drowsiness is frequently reported after vaccination, with decreased appetite and lethargy also occurring, although typically resolving within 24-48 hours 1, 2, 7
Fever that begins ≥24 hours after vaccination or persists for more than 24 hours should be evaluated for other causes, according to CDC guidelines 8, 3
Acetaminophen (15 mg/kg) can be given at the time of vaccination and every 4 hours for 24 hours to reduce post-vaccination fever, as suggested by the CDC 8, 5, 9

Simultaneous administration of vaccines may slightly increase the risk of febrile reactions, but the benefits of timely vaccination outweigh this risk, according to the CDC 10
Patients with minor illnesses with or without low-grade fever can receive vaccination, but moderate or severe febrile illness requires postponing vaccination until the acute phase resolves, as advised by the CDC 11, 8
Contraindications for vaccination include immediate anaphylactic reaction and encephalopathy within 7 days not attributable to another cause, as stated by the CDC 5
Precautions for vaccination include temperature ≥105°F (40.5°C) within 48 hours, collapse or shock-like state within 48 hours, persistent crying ≥3 hours within 48 hours, and convulsions with or without fever within 3 days, according to the CDC 5

Use a fine needle (23-gauge or smaller) for vaccination to reduce hematoma risk, as suggested by the CDC 12, 11
Apply firm pressure to the injection site for at least 2 minutes without rubbing to minimize hematoma risk, as recommended by the CDC 12, 11
For patients with bleeding disorders, schedule vaccination shortly after factor replacement therapy to minimize the risk of hematoma, as recommended by the CDC 12, 11
Have patients lie down or sit in a reclined position during vaccination and ensure the vaccination area has padding or soft surfaces nearby to prevent injury from potential syncope, as advised by the CDC 9
Observe patients for 15-20 minutes after vaccination to monitor for potential immediate adverse reactions, such as syncope, as recommended by the CDC 9
For children with a history of egg allergy receiving influenza vaccine, extend the observation period to 30 minutes, as recommended by the AAP 2, 13

Severe allergic reactions (anaphylaxis) are very rare, occurring in extremely small percentages of vaccinated individuals, and typically manifest within minutes to hours after vaccination, as reported by the CDC 9
For allergic reactions, including anaphylaxis, administer aqueous epinephrine (1:1000) and maintain airway and oxygen if necessary, as recommended by the CDC 9
Document any adverse events in the patient's medical record, including details about timing, associated symptoms, and any resulting injuries, as required by the CDC 14, 9
Report significant adverse events to the Vaccine Adverse Event Reporting System (VAERS), especially serious events, unusual reactions, and events with a temporal relationship to vaccination, as recommended by the CDC 11
Maintain epinephrine and airway management equipment for immediate use and have an office emergency plan in place, as recommended by the CDC 9