Pertussis Vaccine

(1)

0 Committee

on Infectious

Diseases

PEDIATRICS

Vol. 74 No. 2 August

1 984

303

Pertussis

Vaccine

The “Red Book, “ as the Report of the Committee on Infectious Diseases has come to be known, is not a static document, but is subject to frequent revision. Not only does each edition contain new information available to the Committee, but between editions the Committee commu-nicates further changes to the medical profession via Pe-diatrics. These communications constitute “Updates “ to the Red Book. As everyone knows, scientific information proliferates exponentially, and so the Updates have ap-peared more frequently in recent years.

The Update that follows concerns pertussis vaccine, and therefore, it supplements information in the 1982 edition of the Red Book. To place it in context, the entire Red Book section on Pertussis (pp 198 to 202) should be re-viewed, as well as the general sections on immunization,

particukirly the section on Informed Consent (p 4) and the section on Vaccine Dose (p 10).

Like many preventable childhood diseases, pertussis is now infrequently reported in this country. Although more than 200,000 cases were reported annually in the 1930s

0 before pertussis vaccine was introduced, only about 2,000 cases are now recognized each year. The success of the vaccine has resulted in the remarkable decline ofa formerly feared illness. As the incidence of the disease has declined, adverse reactions attributed to pertussis vaccine have re-ceived greater attention and prominence.

In the United Kingdom, following Professor G. T. Stew-art ‘5 alarming reports of brain damage due to pertussis vaccine, immunization rates feliprofoundly, and as a result widespread outbreaks of pertussLs began to occur. In this country as well, there is public recognition that the pertus-sis vaccine produces higher reaction rates than other vac-cines, and in our concern with the reactions there is a danger that we may forget thatpRrtussis, the disease, produces ten times the rate of braindarnage asp.ussis,

the vaccine. Until a better vaccine is available, the risk-benefit ratio has been repeatedly shown to favor the im-munization of children with the presently available per-tussis vaccine (Hinman AR, Koplan JP: Pertussis and I pertussis vaccine: Re-analysis of benefits, risks and costs.

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JAMA, in press 1984). We wish to avoid the resurgence of

I

pertussis outbreaks that occurred in Britain when the level

I

of vaccine utilization was reduced.

But neither do we want to see pertussis vaccine given when prudence and the Red Book Committee suggest it be

I

withheld: when a previous dose resulted in a convulsion,

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encephalitis, focal neurologic signs, or colk.ipse. Nor should

I

infants who experience “excessive somnolence, excessive screaming (persistent crying or screaming for 3 or more

0

hours duration), or temperature more than 105#{176}F (40.5#{176}C)”receive additional doses of vaccine.

Parents, and pediatricians alike, together with the Academy, the federal health agencies, the Congress and vaccine producers, all look forward to the availability of a safer and even more effective pertussis vaccine. Until that time, the Academy urges that parents be informed about the vaccine we have and the disease it is more than 80% effective in preventing, and that infants and children continue to receive the vaccine, on schedule, when there are no contraindications to its use.

PAUL F. WEHRLE, MD

President, American Academy of Pediatrics

A review

of the

current

data

on

the

frequency

and severity of pertussis and also of reactions oc-curring following

administration

of pertussis

vac-cine have

led to some

changes

in recommendations

for immunization with pertussis vaccine. Continued efforts to immunize those who should receive

vac-cine

are

essential

as pertussis

produces

significant

morbidity and may even be fatal; it is particularly severe in

those

who

are

unimmunized.’

The

cur-tailment of pertussis immunization has resulted in epidemics in some countries.2

Infants with a previous

personal

history

of

sei-zures

appear

to be more

likely

to have

a convulsion

following receipt

of pertussis

vaccine.3

There

is no

convincing

evidence

to suggest

that

these

isolated

seizures produce permanent

neurologic

damage

or

aggravate existing neurologic conditions.45 Al-though the risk of vaccine-related seizures in these children is small, the likelihood of contracting per-tussis for most of these children in the United States at this time is also small. It may be prudent,

therefore,

to defer

immunization

of these

children

in order

to eliminate

the

possibility

of their

expe-riencing postimmunization seizures. The decision

to

defer

immunization

should

be reviewed

at each

subsequent

office

or clinic

visit,

evaluating

changes

in risk of exposure and the likelihood of seizures following immunization.

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0

304 PERTUSSIS

VACCINE

INCREASED

RISK

OF

CONVULSION

FOLLOWING

VACCINE

Children

Who

Should

Not Receive

Additional

Doses

of Pertussis-Containing

Vaccine

Children

who

have

a seizure

within

48 hours

following

the

receipt

of a pertussis-containing

vac-cine,

eg, DTP,

should

not

receive

additional

doses

of

pertussis-containing

vaccines.

Because

addi-tional doses of pertussis vaccine are

contraindi-cated,

the

outcome

of

reimmunization

cannot

be

predicted.

Some

of these

seizures

may

be

due

to

fever

caused

by

intercurrent

illnesses4

or fever

in-duced

by

the

pertussis

component

of the

vaccine.

The

risk

of first

seizures

following

pertussis

vaccine

appears

to

be

approximately

1/1,750

immuniza-tions.5

Children

Who

Might

Have

Immunization

Deferred

1.

Children

who

have

had

a personal

history

of

convulsion

at any

time

appear

to have

an increased

risk of convulsions following receipt of pertussis-containing vaccines.

A recent

study

of reports

sub-mitted to the Centers for Disease Control revealed

a sixfold

greater

frequency

of personal

history

of

prior seizure in

children

who

had

a seizure

following

receipt

of DTP

as compared

with

children

who

had

local

reactions

or other

non-neurologic

adverse

re-actions after pertussis vaccine.3 The exact

fre-quency

of seizures

following

DTP

in children

who

have

had

a previous

personal

history

of

non-pertus-sis-vaccine-associated seizure is unknown.

2.

Children

with

certain

neurologic

conditions

(eg,

tuberous

sclerosis,

certain

inherited

metabolic

defects, and other conditions), that might predis-pose to seizures may be at increased risk of convul-sions following receipt of pertussis-containing vac-cines. Prematurity per se is not believed to increase the risk of seizures following immunization.

Addi-tional studies are required of certain categories of

premature

infants,

eg,

those

with

intracranial

bleeding

of varying

severity.

Children

with

devel-opmental

delay

or

cerebral

palsy

without

other

evidence that they have a predisposition to seizures ordinarily would not be considered to be at in-creased risk of seizures following pertussis immu-nization.

CONDITIONS

OF

UNCERTAIN

RISK

OF

CONVULSION

FOLLOWING

IMMUNIZATION

It

has been suggested that the risk of convulsions following receipt of pertussis vaccine is increased if there is a family member who has a nonfebrile seizure disorder,3 or if a sibling has had a seizure following receipt of a pertussis-containing vaccine.

Because of methodologic problems with the study, it is not known whether the risk of postimmuniza-tion seizures is significantly greater in these persons than in the general population. For this reason the

identification

of these

conditions

in

family

mem-bers of the vaccinee is not considered to be reason to defer pertussis immunization at the present time.

RISK

OF

EXPOSURE

TO

PERTUSSIS

1. Infants who attend day care centers or partic-ipate in other activities in which there is increased close contact with other young infants are at greater risk of being infected with a variety of infectious agents that are endemic to their setting or prevalent in the community.

2. Infants and children enrolled in programs or

who

reside

in

institutions

for

the

neurologically

impaired may be in an environment in which a significant proportion of the others with whom they are in contact are not adequately protected against pertussis.6

If

these children should become infected, some believe they may suffer greater morbidity than would normal children. Thus the introduction of pertussis into such a group might lead to both increased spread and more severe illness.

3. There

is a significant

risk

of exposure

to

per-tussis in many underdeveloped countries, in many parts of the western hemisphere including parts of Canada and some developed countries, eg, England,

Japan,

and

others

where

immunization

programs

have

been

less

than

otpimal.

4. At

the present time, the risk of exposure to pertussis in most areas in the United States is relatively low. At times, epidemics of pertussis may occur in certain areas, eg, parts of Oklahoma in i983, and the risk of exposure may be significantly increased.

IMMUNIZATION

SCHEDULES

1. Pertussis vaccine is oridinarily given in corn-bination with tetanus and diphtheria toxoids

(DTP)

starting

at 2 months

of age.

Additional

doses

of DTP are recommended at 4, 6, and 18 months, and a final dose between 48 and 84 months of age. In epidemic situations, immunization may be started as early as 2 weeks of age, and the first three doses can be given as frequently as 4 weeks apart.

2.

In children who are to have pertussis immu-nization deferred, pediatric diphtheria, tetanus tox-oid (DT), should be given in lieu of DTP. If started after 1 year of age, two rather than three doses are to be given followed by a third dose 1 year later. Polio vaccine should be given according to the

regularly

schedule.

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AMERICAN

ACADEMY

OF PEDIATRICS

305 Reassessment

of Children

for Whom

Immunization

Was

Deferred

1. Immunization after infancy of those in whom

.

0

it has been deferred is of considerable value.

Al-though pertussis is most severe in younger infants, it may cause significant illness in older infants, children, and adults. School epidemics have been described. Immunization also may be valuable in decreasing the likelihood of infection of younger siblings.

2.

Deferred pertussis immunization should be reevaluated at each office or clinic visit. Changes in risk of exposure, eg, enrollment in day care or other programs, travel, epidemics of pertussis,

and

others should be assessed.

A reevaluation

of

the

child’s risk of seizures based on observation of frequency of seizures or a clearer understanding of seizure etiology may lead to a decision to immunize

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against pertussis. Pertussis vaccine should be given

if there is no need to immunize against diphtheria and tetanus. It can be obtained only from the Michigan State Department of Health, Biologics

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Division, P0 Box 30035, Lansing, MI 48909. Three

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doses of pertussis vaccine are recommended for the

I primary immunizing series. A fourth dose is given

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1 year following the third dose.

Contraindications for Pertussis Immunization

0 Pertussis

immunization is contraindicated for

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those who have any of the following reactions after administration of a pertussis-containing vaccine: (1) a severe neurologic reaction; (2) persistent un-consolable screaming for three hours or more; (3) a

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hyporesponsive, shock-like state; (4) temperature

of 40.5#{176}C (105#{176}F) or greater, unexplained by

an-!

other cause within 24 hours following

immuniza-tion; (5) a convulsion within 48 hours following immunization; or (6) an allergic reaction to the : vaccine.

0 FRACTIONAL

DOSES

OF

PERTUSSIS

VACCINE

1. Giving smaller than recommended doses to those with “contraindications” cannot

be

recom-mended.

Administration

of mu’IttThimaller

doses

increases the risk of association with untoward events that may be unrelated to the vaccine. There is no evidence, moreover, that smaller doses will decrease the likelihood of contraindicated reac-tions. Indeed one child who had a convulsion fol-lowing DTP immunization may have had a similar reaction to a subsequent fractional dose.

2. Giving smaller doses at different visits will reduce local reactions but may also reduce serologic response.8 Whether children who receive multiple small doses of pertussis vaccine are adequately pro-tected against disease is unknown.

DEVELOPMENT

OF

NEW

PERTUSSIS

VACCINE

Work is in progress toward the development of an improved pertussis vaccine. Development of a

new

vaccine,

or

the

administration

of DT

rather

than DTP will not eliminate temporally associated but etiologically unrelated events that occur at the ages when children ordinarily receive their immu-nizations.

It is unlikely

that

a significantly

better

vaccine will be available for many years. Continued immunization with

the

current

vaccine

of children

for whom it is not contraindicated is strongly rec-ommended.

COMMITTEE ON INFECTIOUS DISEASES, 1983-1984

Philip

A.

Brunell,

MD,

Chairman

James W. Bass,

MD

Robert S. Daum,

MD

William B. Gamble, Jr,

MD

G. Scott

Giebink,

MD

Caroline Breese Hall,

MD

Georges Peter, MD Stanley A. Plotkin, MD

Liaison Representatives

Alan

R. Hinman,

MD

William

S. Jordan,

Jr,

MD

John

C. Petricciani,

MD

David Scheifele,

MD

AAP

Section

Liaison

John

A. Anderson,

MD

REFERENCES

1. Pertussis surveillance, 1979-1981. MMWR 1982;31:333-336 2. Robinson RJ: The whooping-cough immunisation

contro-versy. Arch Di.s Child 1981;56:577-580

3. Adverse Events Following Immunization: Surveillance: Re-port No. 1, 1979-1982. Atlanta, Centers for Disease Control, in press 1984

4. Hirtz DG, Nelson KB, Ellenberg JH: Seizures following childhood immunizations. J Pediatr 1983;102:14-18

5. Cody CL, Baraff U, Cherry JD, et a!: Nature and rates of adverse reactions associated with DTP and DT immuniza-tions in infants and children. Pediatrics 1981;68:650-660 6. Miles RN, Hosking GP: Pertussis: Should we immunise

neurologically disabled and developmentally delayed chil-dren? Br Med J 1983;285:318-320

7. Pertussis outbreak-Oklahoma. MMWR 1984;33:2-1O

8. Baraff U, Cody CL, Cherry JD: DTP-associated reactions: An analysis by injection site, manufacturer, prior reactions, and dose. Pediatrics 1984;73:31-36

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1984;74;303

Pediatrics