10.1 Recipients of any vaccine should be observed for an immediate adverse reaction and should remain under observation until they have been seen to be in good health and not to be experiencing an immediate adverse reaction. As vaccines are administered subcutaneously or intramuscularly, the time of onset of anaphylaxis is variable and onset may be delayed for up to 72 hours. Patients should be advised to seek medical attention if they develop early symptoms such as breathlessness, swelling and rash. Parents should be advised to seek medical advice should unexpected symptoms develop after immunisation. All cases of anaphylaxis should be reported using the Yellow Card scheme.
Anaphylaxis is typically rapid and unpredictable with variable severity and clinical features. The most serious features include cardiovascular collapse, bronchospasm, angioedema, pulmonary oedema, loss of consciousness and urticaria. Asthmatic patients often develop bronchospasm during anaphylaxis. Anaphylaxis generally responds promptly to parenteral adrenaline.
10.3 In the three year period from June 1992, there were 87 spontaneous reports in people of all ages through the Yellow Card scheme of all types of anaphylaxis, following immunisation (excluding MR vaccine which is considered separately below) received by the MCA. No deaths were reported. In that time, over 55 million doses of vaccines were supplied to hospitals and GPs.
10.4 During the national Measles and Rubella Immunisation Campaign in November 1994, approximately 8 million children between the ages of 5 and 16 years (up to 18 years in Scotland) were immunised. 81 cases of anaphylaxis were reported; a reporting rate of approximately one in 100,000 children. There was a slight preponderance in children aged 9 years and older and in females. All children with anaphylaxis, for whom there is information available, appear to have made a full recovery.
10.5 Anaphylactic reactions to vaccines are therefore probably very rare, but they cannot be predicted and have the potential to be fatal. Most anaphylactic reactions occur in individuals who have no known risk factors, making it difficult to advise on special precautions. It is uncertain whether a history of hypersensitivity significantly increases the risk of anaphylaxis.
Findings from the Measles/Rubella Immunisation Campaign of November 1994 suggest that medical and nursing staff can have difficulty distinguishing between anaphylactic reactions, convulsions and fainting. It is important that health professionals involved in immunisation are able to distinguish these conditions. Most convulsions reported after measles and rubella vaccine occurred within one hour of immunisation and had features suggesting syncope rather than epileptic fits. Syncope occurs commonly after any injection such as an immunisation in adults and adolescents. Very young children rarely faint and sudden loss of consciousness at this age should be presumed to be anaphylaxis if a central pulse (such as the carotid) cannot be felt. A central pulse is maintained during a faint or convulsion.
10.6.2 Anaphylaxis can occur without warning. Therefore, adrenaline and an appropriate sized oral airway must always be immediately available whenever immunisation is given. All health professionals responsible for immunisation must be familiar with techniques for resuscitation of a patient with anaphylaxis to prevent disability and loss of life.
VERY YOUNG CHILDREN RARELY FAINT AND SUDDEN LOSS OF CONSIOUSNESS AT THIS AGE SHOULD BE PRESUMED TO BE ANAPHYLAXIS IN THE ABSENCE OF A STRONG CENTRAL (CAROTID) PULSE, WHICH PERSISTS DURING A FAINT OR CONVULSION.
TREATMENT: The patient should remain lying down for 10-15 minutes with their feet raised. At any age, if in doubt, treat the patient for anaphylaxis.
REPORT ALL CASES OF ANAPHYLAXIS TO THE CSM USING YELLOW CARDS.
10.7.1 The reaction should be reported to the Medicines Control Agency using the Yellow Card scheme.
10.8.1 Adults: 0.5 to 1.0ml repeated as necessary up to a maximum of three doses. The lower dose should be used for the elderly or those of slight build.
| Age | Dose of adrenaline |
| Less than 1 year | 0.05ml |
| 1 year | 0.1ml |
| 2 years | 0.2ml |
| 3-4 years | 0.3ml |
| 5 years | 0.4ml |
| 6-10 years | 0.5ml |
10.8.3 Slow intravenous injection may be considered only in extreme emergency. Dilute adrenaline (1/10,000) should be used for the intravenous route. Where intramuscular injection might still succeed, time should not be wasted seeking intravenous access. Patients should be monitored after intravenous administration as adverse effects may be more common when the drug is administered in this way.
| Age | Dose of chlorpheniramine maleate |
| up to 1 year | 200µg/kg body weight |
| 1-5 year | 2.5-5mg/kg body weight |
| 6-12 years | 5-10mg/kg body weight |
| over 12 years | 10-20mg/kg body weight |
By slow intravenous injection over 1 minute
This table is based on the Alder Hey book of chiildren’s doses which provides guidelines on suitable doses of chlorpheniramine maleate for children. Chlorpheniramine maleate is not licensed for injection in children and clinicians take responsibility for its use in this group.
| Age | Dose of hydrocortisone |
| up to 1 year | 25mg |
| 1-5 year | 50mg |
| 6-12 years | 100mg |
| adult | 100-500mg |
By slow intravenous injection
Treatment of acute anaphylaxis. Fisher M. BMJ 1995; 311: 731-3
Treatment of acute anaphylaxis. BMJ 1995; 311: 1434-6
Treatment of acute anaphylaxis. Fisher M. BMJ 1995; 312: 637-8
Adverse reactions to Measles/Rubella Vaccine. Current Problems in Pharmacovigilance 1995; 21; 9-10
The use of adrenaline for anaphylactic shock (for ambulance paramedics). Resuscitation Council (UK) and the Joint Royal Colleges and Ambulance Liaison Committee, March 1996
Treating anaphylaxis with sympathomimetic drugs. Fisher M. BMJ 1992; 305: 1107-8
Adverse events associated with childhood vaccines : Evidence bearing on causality. Ed. Stratton K R et al. National Academy Press, Washington DC 1994