Consultant Family Physician
Qatif Primary Health Care,
P.O. Box 545, Qatif 31911, Saudi Arabia
Tel: +966 3 852 6834
Fax: +966 3 855 1332
Abdul Rauf Mohammed, DIH
Coordinator, Immunization Services
Qatif Primary Health Care
Ghazi Al-Qatari, PhD
Director, Qatif Primary Health Care
A pre-stratified systematic random
sample of 836 children of less than 2 years was
selected in 6 primary health care (PHC) centers
in Qatif district. Companions were instructed
to monitor adverse events for 3 consecutive days
following diphtheria, tetanus and pertussis (DTP)
immunization. There was one or more adverse events
(AE) noted in 96.9 % vaccinees. Local reactions
at the injection site were reported in 91.7%.
Systemic reactions including fever, prolonged
crying, vomiting, and hypotonicity were reported
in 79 %, 24.3%, 9.9% and 1.1%, respectively. Behavioural
reactions including sleepiness, anorexia and fussiness
(irritability) were reported in 42.2 % of vaccinees.
High fever, severe swelling and severe redness
occurred in 5 %, 1 % and 1 % of cases, respectively.
No serious adverse events were noted.
In conclusion, incidence and nature
of AE following DTP are similar to those of internationally
reported figures. No cases of local abscess were
reported. This reflects a comparable safety of
vaccination practice in Saudi Arabia.
Key Words: DTP; Saudi; adverse
events; vaccine;, immunization; safety; Qatif
Saudi Arabia has achieved, during the
last three decades a tremendous achievement in terms
of basic vaccination coverage.1 This has been carried
out, mainly, by structured vaccination programs delivered,
mainly, through a wide network of primary health care
However, a debate is rising about the
safety of this program, especially, in the absence of
effective surveillance of adverse events.
This study was undertaken to survey the
adverse encounters following DTP vaccination and to
compare them with the internationally published figures.2-13
This comparison may serve as an indicator for safety
of the practice.
In Saudi Arabia, the incidence of such
reactions related to licensed vaccines has not been
A population of more
than 350,00014 individuals is served by 26 PHC centers
in Qatif District. All of these centers provide vaccination
services for whole population in their assigned catchment
areas. A total number of 18,898 doses of DTP vaccine
were given to children 0 to 2 years old, in the year
preceding the study.15
A weighted, systematic,
random sample of 6 (23%) PHC centers were chosen after
stratification by the total number of doses of DTP vaccine
given in the year preceding the study, in each center.
In each sampled center, one out of four Saudi infants
and children aged 0 to 2 years routinely attended for
DTP vaccination, and were included using systematic
random sampling, in the period from 2 Sep 2000 until
1 Sep 2001.
Informed consent was
obtained from parents or companions to conduct the surveillance
of adverse events following immunisation (AEFI.) A leaflet
was handed to the companion for introduction of the
study, as well as instructions for monitoring AEFI.
Companions who refused to be included in the study were
A study nurse filled
a basic data questionnaire (no. 1) at the time of vaccination.
The questionnaire contained 37 elements about demographic
data, type of feeding, past and present medical history,
weight, temperature, previous AEFI, education level
of the mother, dose number of DTP, experience of vaccine
provider, timing of vaccination, site of vaccination,
needle size and manufacturer, any medication given pre
or post vaccination, and any massage given to the child
post vaccination. Preferable timing of phone calls was
agreed upon with the companion.
The companion was asked
to monitor the child for fever, change in mood and behavior,
general appearance, and local reactions for 3 days post-vaccination.
A study nurse telephoned, daily, each family for 3 consecutive
days, interviewing the mother or the guardian for AEFI
in the preceding 24 hours and completing a questionnaire
(no. 2.) This questionnaire contained 24 elements about
occurrence of local and systemic AEFI as defined by
the WHO 10, their temporal occurrence and period. Any
visit to medical services for this purpose was traced,
as well as the use of local applications or antipyretics.
calls were repeated, at least twice on the same day,
or in the next few days, to inquire about AEFI.
One fourth of the sample
was directly observed by a study nurse, to validate
the observations of the mother or the guardian. For
this purpose, companions were told to visit the PHCC
the day following the day of vaccination.
A pilot study of the surveillance was held in a different
PHCC in the Qatif area for one month. Questionnaires
and methodology were modified accordingly.
Study nurses and physicians
were trained on collection of data. Study PHC centers
were visited frequently, to solve any obstacle facing
data collection. Study nurses had frequent meetings
collectively with the authors to share the experience
with each other and get guidance from the authors. Data
filling was verified twice by the authors.
Data were coded, entered
and analyzed by the authors using SPSS package, version
Data collection was
interrupted in one PHCC for 6 months due to administrative
obstacles in that center.
Schedules of vaccination
are predetermined as per the Saudi MOH guidelines for
Non-Saudis were excluded,
due to difficulty to contact by phone and language barrier.
However they constitute a small fraction of the vaccine
used was adsorbed diphtheria, tetanus, and pertussis
vaccine, Pasteur Merieux SV. It was licensed and supplied
by the MOH.
A total number of 4,457
injections of DTP vaccine were given to children, age
6 weeks to 2 years, in the selected six PHC centers
in the period of the study out of which, 836 (18.8%;
397 females and 439 males) had been enrolled in the
study. However, post vaccination clinical reaction data
were collected for 749 (89.6%) injections; 47.3% of
them were female. The remaining 87 (10.4%) injection
recipients did not respond to repeated phone calls or
had out-of-service phone lines. They did not differ,
significantly, in their basic demography as well as
the DTP dose.
All recipients were
given one of four primary immunizations, given usually
to children below 2 years of age. The number of injections
given as 1st, 2nd, 3rd and 4th dose were 183 (24.4%),
182 (24.3%), 196 (26.2) and 188 (25.1), respectively.
The dominant ages of recipients in each dose were 6
to 8 weeks (96.1%), three months (93.4%), five months
(94.9%) and 18 months (90.8%), respectively. Trivalent
oral polio vaccine and hepatitis b vaccine were simultaneously
given to all and 24.1% of recipients, respectively.
The data were collected from mothers in
93.7% of the cases. Their level of education was high
school or above in 429 (57.3%), while illiterates constituted
There was one or more AE noted following
injections in 726 (96.9%) vaccinees. Local, systemic
and behavioural reactions were reported following 687
(91.7%) injections, 619 (82.6%) injections, and 316
(42.2%) injections, respectively. These were further
described in Table 1.
No anaphylactic reaction, anaphylactoid
reaction, hypotonic hypo-responsive episode nor DTP-associated
convulsion occurred. However, hypotonicity, alone, has
been reported in 8 (1.1%) cases.
Incidence of excessive crying is shown
in details in Table 2.
Perceived high fever and severe swelling
and redness (circumferential) each occurred following
less than 5% , 1%, and 1%, respectively. No abscess
was reported at injection site.
Table 3 presents the temporal occurrence
of AEFI with DTP vaccine. The majority (93.4%) of AE
were reported in the first 24 hours following immunization.
Eight recipients had consulted a physician
within the first 24 hours. Five were for fever; one
for induration and redness; one for runny nose; and
one for sleepiness.
Safety of vaccination
practice has been questioned, and many effects have
been proposed, such as lower or higher incidence of
known AEFI, or the presence of unusual AE.
DTP vaccine was
chosen for this purpose for many reasons. The first
is that DTP-associated reactions are well studied and
published in the literature, over the last fifty years.
1-9,11,12,15,17-20 Secondly, DTP is the most frequently
administered vaccine to children.
In this study,
identification of findings was made primarily via the
caregiver. Daily contact to the caregiver might ensure
reporting of adverse events of short duration that might
take place. It might be argued that the caregiver might
not be educated enough to report reliable data. However,
no significant differences were noted between different
educational levels in reporting adverse events, as shown
in Table 1. On the other hand, similar methods of reporting
have been used previously by many researchers.1-4,8,21
On the other hand,
quantifying adverse events objectively is difficult,
resource consuming, and does not cover the whole period
post immunization. Adverse events, in our study, occurred
throughout all time intervals in the first forty-eight
hours following immunization, and were of brief duration.
rate, in this study, was high, approaching 90% of vaccinees
The vast majority
(91% - 96%) of them were age-appropriately immunised.
Age was constant in more than 90% of each dose. This
makes differentiation of incidence of AE on age not
More than 96% of DTP vaccine recipients had some effect
of immunisation noted. This is comparable with incidences
of 93% - 96% reported in other studies. 2,25
On the contrary,
few studies and reports have shown significantly lower
incidence of adverse events.1,4,5,8,12,21 These differences
are attributable to different methodologies or being
retrospective or, merely passive reporting. Many other
variables however, might add to these differences. These
include differences in vaccine preparation, batch numbers,
age of the child, dose schedule, and degree and timing
Most adverse events
occurred in the first twenty-four hours. The majority
of them were in the first six hours. These figures are
comparable with similar results shown by Long and colleagues
in northern America.
were more frequent than fever, other systemic effects,
and behavioural effects, in this study, and in other
studies, as well.2,3,8,11
events, including seizures and encephalopathy were not
noted. The absence of any seizure might be attributed
to an insufficient sample size to trace such events,
which were estimated to be less than one in every 1500
However, few studies
have described similar results to this study, in higher
sample size, even.2,22 Permanent neurological damage
is however much less in prevalence and not within the
scope of this study. It has been reported to occur once
in 32,000 to 1.24 million doses. 9,11,24
defined in this study as excessive continuous crying
or screaming, occurred after 24.3% of injections, while
few other studies have described non-specific definition
after 30 to 63% of injections.25-27
According to our
definition, crying for more than 30 minutes and crying
for more than 3 hours occurred in our study, after 2.9%
and 0.8% of injections, respectively. These figures
are comparable with other studies that showed incidence
of 2 to 6% and 0.1 to 3%, respectively.3,28
of DTP dose appears to affect the incidence and type
of AE. Fever, local swelling and redness, anorexia,
fussiness, and hypotonia occurred maximally after DTP4,
with slight decrease in their incidence after DTP2.
These findings are comparable with similar findings
in other studies.2,3,23,25,27
Incidence and nature of adverse events
following DTP vaccination in Qatif PHCC are similar
to internationally reported figures. They are common,
and worth considering by health workers, in order to
orient caregivers for their possible occurrence at time
The absence of any serious AE might necessitate
a larger sample size to be traced.
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