immunization update - 1996

General Points

1. A viral infection is only a contraindication to vaccination if the child has a fever.
2. Babies born prematurely should receive their vaccinations based on their chronologic age.
3. Eczema is not a contraindication to vaccination.
4. If the recommended vaccination schedule is delayed, there is no need to give extra doses.

Diptheria

• 1 case and 4 carriers reported in Alberta in last 9 years
• primary series given at 2, 4, and 6 months with booster at 18 months
• next booster at 5 years and then every 10 years

Tetanus

• cases reported in Alberta in last 9 years
• given with diphtheria immunization
• give booster with clean, minor wound if over 10 years since last vaccination and with dirty wounds if over 5 years
• if didn't receive a primary series (3 doses and a booster), give another dose with minor wounds and give a dose with Tetanus Immune Globulin for dirty wounds

Pertussis

• vaccine given with diphtheria and tetanus toxoid up to pre-school dose and then not given as morbidity from pertussis minimal after that age and side effects of current vaccine very common (fever, local reaction)
• however, this policy results in adults being susceptible to pertussis and getting unrecognized, mild disease which they spread to children who then get more severe disease
• whole cell vaccine still used here for all doses
• acellular vaccines being used for 18 month and pre-school boosters in the U.S.

Facts to know about acellular pertussis vaccine:

1. This is not a uniform product: different manufacturers include different components of the organism in their vaccine.
2. Most efficacy data is based on immunizing kids over 18 months, so it is not clear how effective vaccine is if used according to the schedule we use. In the older kids, the vaccine seems to be no more efficacious than whole cell vaccine (i.e., about 15% of fully immunized children will still get pertussis following exposure).
3. Acellular vaccine results in less fever and local reactions than does whole cell vaccine, but still can result in seizures and hyporesponsive episodes. Only one small study has looked at using acellular vaccine to immunize adults, so we need more data on safety and efficacy, as adult pertussis immunization may be necessary to eradicate pertussis.

Absolute contraindication to pertussis vaccine:

• anaphylaxis

Relative contraindication to pertussis vaccine:

• hypotonic-hyporesponsive episode

Reason for deferral of pertussis vaccine:

• evolving neurologic disorder

Former contraindications to pertussis vaccine:

1. fever over 40.5
2. high-pitched scream for over one hour
3. crying for over 4 hours
4. seizure within 72 hours of previous dose
5. thrombocytopenia after previous vaccine
6. encephalopathy within 7 days of previous dose

As of 1993, it is recommended vaccine be given despite these reactions to previous doses as there is no proof that pertussis vaccine ever causes chronic neurologic sequelae.

DPT Vaccine

Reactions to DPT vaccine

All reactions should be reported to the Board of Health, and their experts will recommend what further action needs to be taken.

Type I

• anaphylaxis or rash in first hour
• extremely rare

Type II and III reactions

• very common
• get fever and local reaction, which typically occurs 1-3 days after immunization
• local reaction can look just like a cellulitis
• can also cause generalized rash within 48 hours of immunization

Type IV

• delayed local itching
• occurs mainly in adults from diphtheria component

Non-allergic

• fever and sore arm is common
• can also get sterile abscesses from tetanus component which will resolve spontaneously

Prophylactic acetominophen decreases the incidence of fever.
EMLA cream decreases the length of crying after immunization, but is not yet being routinely recommended.

Measles

• MMR given at 12 months
• cases reported in Alberta in 1994 and nil in 1995
• has moved towards a two-dose schedule (15 months and about 14 years) because of recent epidemics
• we like to believe that because we achieve so much better immunization rates than they do, the second dose is not necessary but some studies have shown that many of the children who got measles had been immunized

Mumps

• cases reported in Alberta in 1994
• cases in 1995

Rubella

• cases reported in Alberta in 1994 and 20 cases in 1995
• congenital rubella still occurs!

MMR Vaccine

Reactions to MMR Vaccine

Type I allergic reaction

• could be from neomycin or egg
• refer for skin testing

Mild disease

• occurs in 5-15%
• symptoms include rash and fever, erythema multiforme or URI day 5 to day 12 from measles or rubella
• parotitis may occur later from mumps

Arthralgias or arthritis

• in 15% of post-pubertal females
• more common from natural disease than from vaccine

Acute encephalitis/ SSPE

Guillain-Barre

Should patients with egg allergy be given MMR?

• Yes.

Haemophilus influenzae

• cases of invasive HIB disease in Alberta in 1993 (4 adults, 3 unimmunized children, 2 vaccine failures)
• cases in 1994
• cases in 1995

• vaccine given at 2, 4, 6, and 18 months in Alberta for past 2 years
• need for boosters after 18 months not clear

Polio

• cases of polio in Canada in last 14 years - 8 of these vaccine-associated
• switched from OPV (oral polio vaccine) to eIPV (enhanced inactivated polio vaccine) August, 1994 in Alberta which eliminates the risk of vaccine-associated polio
• available as a Pentavalent vaccine with DPT and HIB

Advantages of OPV:

• results in mucosal immunity (IgA)
• results in virus being in the water supply, so immunizes more than just the recipient of the vaccine
• easy to administer
• until recently, was much less expensive than IPV

Disadvantages of OPV:

• can cause polio (especially with first dose)
• can spread polio to immunocompromised hosts

eIPV Advantages:

• does not cause polio
• no danger of spread to immunocompromised hosts

eIPV Disadvantages:

• manufacturing sufficient quantity of vaccine has been a problem in the past

Hepatitis B vaccine

• cases recognized in Alberta in 1994 and 96 cases in 1995
• vaccine available, safe and effective
• universal immunization would be ideal
• in Alberta, given free of charge to "high risk" groups (infants of carrier mothers, children in households with a carrier, hemophiliacs, hemodialysis patients, children under age 7 from racial groups where hepatitis B is endemic, institutionalized people) but this policy is yet to have an effect on the incidence of disease
• routine vaccination of students in Grade 5 started in 1995-96 school year

Hepatitis A vaccine

• available in Canada as of 1994
• main indication for now will be frequent travellers to endemic areas

Influenza vaccine

• must be given annually
• effectiveness varies from year to year
• implicated as cause of Guillain-Barre in 1976 in Alberta but, since then, seems to be a very safe vaccine
• insufficient data to recommend use in babies under 6 months of age

Pediatric Indications:

1. chronic pulmonary disease (CF, asthma which requires use of daily medication)
2. hemodynamically significant congenital heart disease
3. residents of chronic care facilities
4. children with immunosuppression
5. children with sickle cell disease and hemoglobinopathies
6. children on long-term ASA
7. children with HIV

It is more debatable whether children with diabetes, chronic renal disease, or chronic metabolic disease need influenza vaccine.
Immunization of contacts of high-risk children should be considered.

Pneumococcal vaccine

• does not cover all strains of pneumococcus so not as effective as most other vaccines
• unclear if boosters indicated
• poor immune response in children under 2 years

Pediatric Indications:

1. functional or anatomic asplenia
2. nephrotic syndrome
3. solid organ transplant recipient
4. chronic CSF leak (debatable)
5. HIV infection

Varicella vaccine

• developed in Japan
• licensed in U.S. in 1995
• about 85% of normal hosts protected after one dose
• remainder get mild varicella after exposure
• about 85% of immunocompromised hosts protected after two doses - half get vaccine-associated rash
• side effects minimal
• does not seem to increase the incidence of Herpes Zoster

Dr. J. Robinson
Pediatric Infectious Disease
Department of Pediatrics
University of Alberta
Revised: July 08, 1997