Lumps in the groin

Tetanus immunization of women of childbearing age

The immunization of pregnant women with tetanus toxoid (TT) vaccine is a highly effective means of protecting the newborn child from tetanus. The optimal schedule for this vaccination depends on the immunization history of the woman.

• Schedule A: regions in which women were not vaccinated during infancy and childhood, or where there is insufficient documentation for previously vaccinated women to be identified, should administer a full TT 5-dose schedule for all women of childbearing age. The details of these schedules are presented in the box. The regions concerned need to determine the age group to be included in the schedule (e.g. 15–35 yrs or 15–44 yrs).
• Schedule B: regions in which women have documentation of previous vaccination with TT-containing vaccines during infancy or childhood can apply more selective schedules for tetanus vaccination — see box. (It is likely that more and more countries will start to fall into this group with the worldwide increase in tetanus vaccination during infancy. The EPI recommends that countries start to use schedule B when DTP vaccination during infancy has reached 80%.)

Adverse reactions

Although modern vaccines are extremely safe, some vaccines may lead to adverse reactions. It is difficult to prove that a vaccination causes a specific event. Instead, population studies must be carried out to look for an association between the vaccination and the adverse event (e.g. clustering of cases in vaccines or a higher incidence in vaccinated compared to unvaccinated groups).

Adverse reactions tend to be caused by:

• Faults of administration (programmatic errors): e.g. abscesses after poor mixing of vaccines or use of non-sterile needles or syringes; disseminated disease in immunosuppressed patients after administration of BCG or measles vaccines.
• Properties of the vaccines: the reactions may be caused by the immunizing antigen itself or by other components such as antibiotics (used in growth of the virus), preservatives, or adjuvant.

Mild adverse events are common (e.g. 20–50% of DTP recipients experience mild local reactions while some measles vaccine recipients get a rash and fever). Booster doses of toxoids may induce hypersensitivity reactions in some people.

Severe reactions such as encephalitis after mumps or measles vaccines are extremely rare. DTP vaccination has been reported to be associated with many adverse affects but comprehensive studies have failed to link it to many of these adverse effects. Vaccine-associated severe events are much less common than the severe complications caused by the disease itself.

It is essential to detect serious adverse events and to identify the underlying cause since such reactions will influence community acceptance of the vaccinations and immunization rates.

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Schedule A: TT immunization schedule for women of childbearing age

Dose When to give Expected duration of protection TT-1 At first contact or as early as possible in pregnancy None TT-2 At least 4 weeks after TT-1 1–3 yrs TT-3 At least 6 months after TT-2 5 yrs TT-4 At least 1 year after TT-3 or during subsequent pregnancy 10 yrs TT-5 At least 1 year after TT-4 or during subsequent pregnancy All childbearing years

Schedule B: guidelines for TT immunization of women who were immunized in the past

Recommended immunizations Age at last TT Immunization Previous TT immunizations At present contact Later (at interval of >1 yr) Infancy 3 DTP 2 TT 1 TT Childhood 4 DTP 1 TT 1 TT School age 3 DTP + 1 DT/Td 1 TT 1 TT School age 4 DTP + 1 DT/Td 1 TT None Adolescence 4 DTP + 1 DT at 4–6 yrs and 1 TT (or Td) at 14–16 yrs None None

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Contraindications

There are relatively few absolute contraindications to vaccination. Every opportunity to vaccinate a child or woman of childbearing age should be taken, particularly in outpatient clinics (see ‘missed opportunities’ on p. 656). There is a high risk that delaying vaccination until the child is better will result in that child not getting his/her full complement of vaccinations because he/she did not return again and was lost to follow-up. Many programmes have contraindications which are inappropriate. Such false contraindications are listed in the box.

True contraindications to vaccination include:

• Illnesses severe enough for the child to be hospitalized — if the child is vaccinated but then dies from the pre-existing illness, the vaccine may be thought to have killed the child. However, immunize as soon as the child's general condition improves. Give measles vaccine on hospital admission if possible because of the risk of nosocomial transmission.
• For live vaccines, immunodeficiency diseases or immunosuppression due to malignant disease, therapy with immunosuppressive drugs, or irradiation. HIV/AIDS is a special case — see below.
• A severe adverse event (anaphylaxis, collapse or shock, encephalitis, encephalopathy, or non-febrile convulsion) after a previous dose of vaccine. If the adverse reaction occurs with a dose of DTP vaccine, omit the pertussis component and complete the vaccination with the DT vaccine.
• For vaccines prepared in egg (yellow fever, influenza) a history of anaphylaxis following egg ingestion. Vaccines prepared in chicken fibroblast cells (measles or MMR) can usually be given to such people.

Live vaccines should not be routinely administered to pregnant women except where there is a high risk of exposure and the need for vaccination outweighs any possible risk to the fetus. In adult women, pregnancy should be avoided for >1 month after vaccination with a live vaccine. Live vaccines include:

• BCG
• measles
• mumps
• oral polio vaccine (OPV).
• yellow fever
• typhoid
• rubella

Immunization of HIV-infected persons

There has been concern that HIV-induced immune system impairment might make HIV-infected people more susceptible to severe vaccine associated diseases. There has so far been no evidence to support this concern. Instead, since both measles and TB are associated with higher mortality in HIV +ve patients, there is clearly a great need for these persons to be vaccinated. Most HIV +ve infants and adults are able to mount a good immune response to vaccination and should receive all EPI vaccines as early as possible.

The WHO/UNICEF guidelines for immunization of HIV-infected individuals are presented in the box opposite.

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Conditions which are NOT contraindications to immunization and which MUST NOT prevent a child from being vaccinated

• Minor illnesses such as URTI or diarrhoea, with fever <38.5°C
• Allergy, asthma, other atopic manifestations, hay fever, or snuffles
• Prematurity, small for date infants
• Malnutrition
• Child being breastfed
• Family history of convulsions. (However, if there is a Hx of febrile convulsions, offer advice on the treatment of fever before giving vaccine — for a 2–3 month infant, give 60 mg paracetamol followed by a 2nd dose 4–6 hrs later if required. Advise parents to see a doctor if the fever persists after a 2nd dose of paracetamol.)
• Treatment with antibiotics, low-dose corticosteroids, or locally acting (e.g. topical or inhaled) steroids
• Dermatoses, eczema, or localized skin infection
• Chronic diseases of the heart, lung, kidney, and liver
• Stable neurological conditions, such as cerebral palsy and Down's syndrome
• History of jaundice after birth

WHO/UNICEF recommendations for the immunization of HIV-infected children and women of childbearing age

Vaccine Asymptomatic HIV infection Symptomatic HIV infection Optimal timing of immunization BCG Yes1 No Birth DTP Yes Yes 6, 10, 14 weeks OPV2 Yes Yes 0, 6, 10, 14 weeks Measles Yes Yes 6, 9 months3 Hepatitis B Yes Yes As for uninfected children Yellow fever Yes No4 TT Yes Yes 5 doses — see above 1 . If the local risk of TB infection is low, then BCG should be withheld from individuals known or suspected to be HIV infected. 2 . IPV can be used as an alternative in symptomatic HIV +ve children. 3 . Because of the risk of severe early measles infection, HIV +ve infants should receive measles vaccine at 6 months and as soon after 9 months as possible. 4 . Pending further studies.