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Original Article
2 (
1
); 18-28

Post-marketing Surveillance on Safety of Japanese Encephalitis Vaccine SA 14-14-2 in Burdwan District of West Bengal, India.

Associate professor, Community Medicine, R. G. Kar Medical College, Kolkata,
Professor, Pediatric, North Bengal Medical College, Darjeeling;
Associate Professor, Dept. of Com. Med, RG Kar Medical College, Kolkata
Associate professor, Community Medicine, IPGMER, Kolkata;
Associate professor, Community Medicine, Murshidabad Medical College, Berhampore;
Asst. professor, Community Medicine, R. G. Kar Medical College, Kolkata.
Corresponding Author: Dr. Dibakar Haldar, Assoc. Professor, Community Medicine, RGKMC, Kolkata-4. Resident: Anandapalli, Sitko Road, Duttapara, Baruipur, Kolkata-700144; E-mail: dibahaldar@gmail.com ; Telephone number (mo): 9433588427.

Address for correspondence: The Editor/ Managing Editor, Journal of Comprehensive Health Dept of Community medicine NRS Medical College, 138, AJC Bose Road, Kolkata-700014

Licence
This open access article is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0). http://creativecommons.org/licenses/by/4.0

Abstract

Background

- Japanese Encephalitis with high mortality and disability is serious public health menace in South-East Asia including India. Successful JE control of other S.E.Asian countries and the largest epidemic in Uttar Pradesh, led India to initiate mass vaccination campaign, in 2006, for immunizing 1-15 years children of eleven hyperendemic districts of five states with SA-14-14-2 JE vaccine.

Methodology

- Community based Active Postmarketing Surveillance for one year was conducted, in randomly selected villages of a randomly selected block of Burdwan district, West Bengal, involving 720 target children with objective to explore the safety of SA-14-14- 2 vaccine, in Indian perspective.

Results

- About 15% and ≤1% participants suffered from pain and swelling and/or redness at injection site. Fever was the most prominent general systemic reaction developed by about 10-15% subjects, < 5% children reported reactions like headache, bodyache, nausea-vomiting, listlessness, loss of appetite, pain abdomen and loose motions etc. whereas almost 5-8% vaccinees affected by cough and runny nose. No serious AEs was reported up to one year after vaccination.

Conclusion

- Being consistent with results of other studies, present findings led to conclude that short term safety of vaccine appeared satisfactory requiring long term monitoring of AEFIs to explore its remote serious AEs.

Keywords

mass vaccination campaign
active post marketing surveillance
serious adverse events
local reactions
general systemic reaction
specific systemic reactions
JE vaccine SA-14-14-2

Introduction:

Japanese Encephalitis (JE) also called brain fever caused by JE virus, a RNA virus belonging to Flaviviridae family of Group-B arbovirus, is a mosquito (Culicine mosquitoes notably C. tritaeniorhynchus, C. vishnui) borne viral encephalitis in S.E. Asia with more than 20% case fatality and 30-60% neuropsychiatric disability among the survivors.1,2,3,4 About 60% of the world’s population live in JE endemic regions and approximately 50000 cases with 10000 deaths per annum were notified from a wide geographic range.1 In India JE is responsible for approximately 2000-3000 clinical cases and 500-600 deaths per annum reported from all states and Union Territories of country except Arunachal Pradesh, Dadra, Daman, Diu, Guj arata, Himachal Pradesh, Jammu & Kashmir, Lakshadeep, Meghalaya, Nagar Haveli, Orissa, Punjab, Rajasthan and Sikkim. West Bengal, Bihar, Tamil Nadu, Andhra Pradesh, Uttar Pradesh, Assam, Karnataka, Manipur and Goa are hyperendemic states with highest risk at monsoon/post monsoon time among 1-15 years children living in rural areas.2 Having very complex epidemiological features with multiple hosts and vectors JE virus becomes a part of ecosystem and is too difficult to eradicate. Vaccination remains the single most important cost-effective control measure. 2,5 Immunization with an effective, safe, cheap, simple to administer vaccine being the only way of JE control should be extended to all areas where it is a demonstrated public health problem and needs incorporation into routine immunization programme (W.H.O./SEARO/2006; W.H.O.J.E. position paper, 2006; Bi-regional JE meeting, 2005, WHO/PATH). Japan, China, Korea Republic, Thailand and Nepal have controlled JE to large extent using vaccine.6,7 India uses 3 doses of killed mouse brain JE vaccine prepared at Kasauli, HP since 1988 and hasn't included in routine immunization programme as JE risk is not universal rather focal.8,9 But in the face of expanding JE affected areas, scarcity of costly mouse brain vaccine10,11 and above all being witnessed by massive JE outbreak in 2005 resulting in 2000 deaths and even greater disabilities in UP and Bihar;2,3 the government of India (GOI) supported by Programme for Appropriate Technology in Health (PATH) initiated a pilot project in 2006 for immunizing children aged 1-15 years in eleven hyper-endemic districts of five states (five districts of UP, two from Bihar & Assam each, one of Karnataka & West Bengal each) by a single dose cheap11 live attenuated SA 14-14-2 JE vaccine prepared and marketed by “Chengdu Institute of Biological products”, China, and appeared to be safe and effective as per several trials held in China, South Korea, Nepal etc..13-15 The GOI purports expansion of JE vaccination coverage in phased manner to include all high risk areas by 2010 and incorporation of it in national immunization schedule.2,10,11 Side by side by the help of PATH and Society for Applied Studies (SAS) GOI also arranged “An Open Label, Multicenter, Post Marketing Study” to evaluate the safety and immunogenecity of single dose Live attenuated SA 14-14-2 JE vaccine in Indian perspective.10 Authors were part of the Post marketing surveillance project and paucity of information regarding the safety of live JE vaccine in Indian subcontinent indulged them for contemplating the present study with following

objectives-

  • To describe the magnitude and pattern of adverse events following immunization (AEFI);

  • To assess the serious AEFIs of the vaccine within 12 months of post vaccination period;

  • To find out the relation between few attributes of the vaccinees and AEFIs

Methodology:

It was a community based observational follow up study from June, 2006 to August, 2007 with a vaccine cohort comprising of both sexes of 1-15 years children. Out of the eleven hyperendemic districts selected for mass vaccination campaign in 2006; Burdwan, West Bengal and Bellary, Karnatak were randomly selected for post-marketing surveillance.10 The present study was limited in Burdwan, West Bengal where the Block Memary-1 with Gram Panchayat (GP) and villages were selected randomly from the list of Blocks of Burdwan district, list of GPs with their villages of Memary-1 block. Village Purbagantar, Gantar, Dakshingantar of Gantar GP and Kashiara, Mallikapur, Mogra, and Shankarpur of Radhakantapur GP were selected for the purpose. In next step, consecutive children of both sexes from the selected villages were included in the study with subsamples of ≥200 children adjusted with 20% drop out for each age group of 1-5, 6-10 and 11-15 years. Thus, 720 children were involved in the study. Thirty young graduates were deployed as Field Investigators (FIs) after thorough training by the supervisors, Principal and Co-principal Investigators (PI &CoPI) who were all doctors and trained about the project by SAS at its head office at New Delhi. Village identification and area allocation to the FIs was done by the help of Panchayat personnel. List of potentially willing beneficiaries from selected villages was prepared by FIs along with panchayat personnel conducting a door to door survey when a notice regarding the vaccination & study was read out to the families having children aged 1-15 years and were called to a destined place on scheduled date of vaccination (four vaccination posts held at Gantar G P from 24th to 27th June, 06 and four posts at Radhakantapur GP from 7th to 10th July,06. On the vaccination day FIs were to ensure that children were brought to the immunization sites. Guardians of these children were briefed about the purpose, risks-benefits and voluntary nature of the participation clearly and all their queries were answered by supervisors, PI - CoPI. After obtaining written consent and assent (if necessary), the children were screened thoroughly by the supervisors using proforma containing predesigned exclusion/inclusion criteria. Selected children were then vaccinated by the Auxilliary Nurse Midwives (ANMs) and meticulously observed for minimum 30 minutes by a supervisor. Then, he/she was offered a participant card. The weight and height for a subsample of 360, who consented for giving blood samples for immunogenecity part of the study;10were measured as per standard methods and documented before vaccination. The children who refused to participate in study and/ or disqualified in screening were sent to ANMs for vaccination as other than study participants. Subsequently, daily home visits were paid to all participants from the late part of the vaccination day through 7th post vaccination day by the FIs to obtain information on any illnesses or AE after vaccination. Then, the FIs made home visits and / or contacted the enrolled child and his/her parents through telephone or visited the child's school on 14th (±2), 21st (±2) and 28th (±2) post vaccination days for collecting informations on any illnesses or AEs occurred since previous visit. Afterwards quarterly visits at home or school on 3rd (±7days), 6th (±7days), 9th (±7days) months, and 1 year (±14days) after vaccination were made to ascertain any serious AEs occurred. During each visit, the child was thoroughly examined by FIs to explore any AE of the vaccination or any illness. He/she was to record the AEs detected by him/her or stated by the care givers in predesigned formats, earmarked separately for each day's field visit, handed over to him/her after demonstration. FIs had to measure the body temperature, local swelling or redness at site of injection, if present at the time of visit, for which necessary equipments were demonstrated and supplied. They had to submit their filled up formats to the respective supervisor at the end of visits. If a family was not available on the day of visit, two repeat visits were paid on that day and daily subsequently, till the child was contacted. If the family was not available for seven consecutive days or if information was received that the family left their home, the child was censored for the study and deemed lost to follow up. The families of enrolled children were asked to consult the principal investigator and or bring their children along with the participant cards offered to them (for identification of study subjects) to the Memari rural hospital or Burdwan Medical College in case the child had any symptom or illness. All the FIs were provided with supportive supervision and close monitoring by supervisors during field work. At the end of each day's visit, all the formats were scrutinized by respective supervisors and then the PI along with CoPI checked these format for grading and relating the AE, if any, with vaccination based on the guidelines provided thereon and handed over to SAS, Delhi for data entry, if the AEs were graded as I & II; faxed to Independent Safety Monitor (ISM), Delhi when the AEs were earmarked as Grade-III and faxed filled up Serious Adverse Events (SAE) form urgently within 24 hours to ISM, SAS, ICMR in any case the AEs were grouped as grade IV (serious/life threatening/death).Thus, at the end of the study at August, 07, complete data for 712 study subjects were available and analysed by using proportion, χ2 test etc. Another extra visit was paid to all study subjects on January, 2009.

Results and Discussion:

Male participants was 51.4% and 33.8%, 33.6% and 32.6% study subjects belonged to the age group 1-5 , 6-10 and 11-15 years, respectively. No AE whatsoever was reported within 30 minutes after vaccination. Analysis of information obtained up to 96 hours after vaccination showed that among local reactions, pain affected 14.46% of vaccinees with mean duration of 1.51±0.69(m±sd) days followed by swelling and redness (2.5-5cm) at injection site troubling 1.54% and 0.56% of subjects with mean duration of 1.73 ±0.9 and 1.5±2.0 days, respectively (table-1). Among the general systemic reactions occurred within this period, fever affected 10.67% of vaccinees with mean duration of 1.83±1.08 days; followed by headache (4.77%), body-ache (3.51%), dizziness (3.08%), nausea (2.24%) , listlessness (3.67%), loss of appetite (3.23%) with mean duration of 1.38± 0.6 ,1.68± 0.84 ,1.45±0.72 ,1.68±0.84 ,1.42±0.6 , and 1.82±0.91 days, respectively (table-1).

Table-1: AEs developed amongst the vaccinees (N=712).
Adverse reactions ≤96 hrs. 5-28 days,
Local Pain at site 103(14.96) ----
Swelling 11(1.54) -----
Redness 04(0.56) ------
General Fever* 76(10.67) 104(14.6)
Headache 34(4.77) 14(1.96)
Bodyache 25(3.51) 09(1.26)
Dizziness 22(3.08) 04(0.56)
Chill 06(0.84) ---
Nausea 16(2.24) 10(1.4)
Vomiting 11(1.54) 15(2.1)
Listless 19(2.67) 07(0.98)
Rash 04(0.56) 02(0.28)
Loss of appetite 23(3.23) 25(3.5)
Irritable 06(0.84) 01(0.14)
Weakness 01(0.14) 03(0.42)
Skin irritation 01(0.14) 01(0.14)
Yellowish urine 01(0.14) 01(0.14)
System
involved
predominanti
y
RTI Cough 54(7.58) 46(6.46)
Runny 41(5.75) 35(4.91)
Sore --- 06(0.84)
GIT Pain 22(3.08) 19(2.66)
Loose 19(2.67) 12(1.68)
CNS Convulsio -- 01(0.14)
Miscellaneous 11(1.54) 20(2.8)

More than 1 million children have been followed in a safety study showed side effects were rare, most common being transient fever in approximately 5-10% and local reactions, rash or irritability in 1-3% of vaccinees. Neither acute encephalitis nor hypersensitivity reactions have been associated with this vaccine.15 Similar results have been obtained from a randomized control trial with 26239 subjects14 and from post-marketing surveillance conducted in South Korea since 2002.15 As per report of the Bi-regional meeting on JE, WHO-2005; local reactions in the form of pain, swelling and redness at site found in less than 1%, mild systemic reactions like headache, myalgia, Gastro-Intestinal (G I) symptoms, low grade fever (<0.5%) etc. found in total 21% of subjects with no report of hypersensitivity or encephalitis. Local reactions, within seven days of post-vaccination period included redness (< 1%), swelling (1% to 5%) and pain (5% to 10%). The most common systemic symptom was fever (12%).11.

So far as the specific systemic reactions revealed by the present study, the vaccine seemed to affect the Respiratory Tract (RT) mostly e.g. 7.58% and 5.75% study subjects suffered from cough and runny nose with mean duration of 2.7 ±1.75 and 3.0±1.84 days. However, 3.1% and 2.8% participants also suffered from pain abdomen and loose motion with mean duration of 1.5±1.83 and 1.8±1.16 days (table-1). Most of these symptoms were mild necessitating medication for 12.2% of affected participants with a mean duration of 2.2±1.55 days but no hospital admission and restricted activity of daily living (ADL) was reported so far. Two participants having high fever for 7 and 8 days (positive Widal test), with some interference of ADL (moderate = grade-II) were excluded from analysis because fever inherent to inoculation didn't persist so long and these two cases were considered coincidental illness. On the whole 14.5% participants were affected by local reactions amongst which 93.3% took place on the day of vaccination. On the other hand 40.7% and 28.2% of the general systemic reactions occurred on the day of vaccination and 1st post vaccination day. Out of the specific systemic symptoms, 43.4% and 31.6% were reported on the day of vaccination and 1st day after vaccination.

During 5-28 days of post vaccination period, mentionable general systemic symptoms were fever, headache, bodyache, nausea, vomiting, loss of appetite etc. affecting 14.6%,1.96%, 1.26%, 1.4%,2.1% and 3.5% of vaccinees, respectively (table-1). During this period, one fellow developed one spell of seizure and another developed jaundice with some interference of ADL but were not hospitalized. Apart from these two moderate (grade-II) AEs, all symptoms were mild in nature where 45.4% of the affected participants (163) had to use medicine but without hospitalisation or restriction of ADL. In a study in West China, no serious AEs have been reported within 30 days follow up in 13266 children. Rate of AEFIs was 4.1/10000 after 1st dose.13 In a comparative observational study with approximately 26000 subjects in China most common reactions were fever, rash, vomiting and no serious reactions were found within 30 days follow up.18 Information from both active and passive post-marketing surveillance in Republic of Korea where the SA-14-14-2 was first licensed in 2001 showed that of 522 vaccinated children actively monitored for AEs for 4 weeks after vaccination, approximately 10% developed fever higher than 380C and cough. Redness-swelling at site of injection observed in < 1%.These findings were consistent with those reported from China. 18Scott B H et al reported that numerous large scale evaluations of vaccine safety demonstrate low rates (0.2%-6%) of short-lived local and systemic (i.e. fever) reactogenicity and essentially no neurotoxicity.19 Saxena P observed in his study in Bareilly that this vaccine was found very safe, out of the 2279 vaccinated children only 6.6% children were suffered from swelling and 3.5% children suffered from fever.20 There was no major AE due to this vaccine like encephalitis, meningitis, respiratory distress, anaphylaxis and death during or after campaign.20

It was revealed from the analysis that all immediate AEs (as considered up to 96 hrs after vaccination) e.g. local, general and systemic affected almost equal proportion of candidates in three age categories but general and systemic reactions during 5-28 days interval after vaccination involved significantly more fellows from the lowest age group (table-2).

Table-2: Distribution of vaccinees developed one or more AE(s) up to 4 weeks after vaccination
Age gr. Follow up Interval
≤96 hrs, No.
(%)
χ2 at df 2, p 5-28 days, No.
(%)
χ2 at df 1, p; RR (95%CI)
1-5 yrs [n1=241] 76(31.5) 0.05,
0.97306719
86(35.68) 23.37, 0.0000013; 2.19 (1.57
3.05)
6-10 yrs
[n2=239]
75(31.38%) 39(16.3) *
11-15 yrs
[n3=232]
71(30.6%) 38(16.4) 0.00, 0.9856461;1.00 (0.67
1.51)
Total [N=712] 222 (31.2) ------- 163 (22.9) 12.39, 0.0004312;1.36 (1.15-
1.62)#

Among the AEs local reactions were reported significantly less from lowest age category in comparison to their counterparts whereas the general systemic reactions found to be equal across the age groups (table-3). Again specific systemic involvement within first 96 hours and both general and specific systemic reactions observed during 5-28 days after vaccination were reported to be declined significantly with advancing age (table-3) conforming to existing knowledge.2

Table-3: Distribution of vaccinees developed one or more AE(s) up to 4 weeks after vaccination
Follow up interval AEs 1-5
yrs[n1=76]
No. (%)
6-10
yrs[n2=75]
No. (%)
11-15 yrs
[n3=71]
No. (%)
χ2, p at df 1* RR (95% CI)*
≤96 hrs.
[n1=222]
Local 27(35.5) 44(58.6) 34(47.8) 8.11.0. 0043921
1.70.0. 1918762
2.31.0. 1285191
0.61 (0.42-0.87)
1.23 (0.90-1.67,
0.74 (0.50-1.09)
General 43(56.57) 42(56.0) 47(66.2) 0.01,0.9428322
1.59.0.2068184
1.43.0.2316964
1.01 (0.76-1.34)
0.85 (0.65-1.10)
0.85 (0.66-1.11)
Systemic 46(60.5) 33(44.0) 22(30.98) 4.13.0. 0420597
2.63.0.1048058 12.89,
0.0003312
1.38 (1.01-1.88)
1.42 (0.92-2.18)
1.95 (1.32-2.89)
5-28 days [n2=163] General 60(78.9) 27(36.0) 30(42.2) 28.51.0. 000000 1
0.60,0.4388386
20.82.0. 000005 0
2.19 (1.59-3.03)
0.85 (0.57-1.28)
1.87 (1.39-2.51)
Systemic 45(59.2) 15(20.0) 19(26.76) 24.24.0. 000000
9
0.93,
0.3340514
15.72.0.000073 3
2.96 (1.81-4.83)
0.75 (0.41-1.35)
2.21 (1.44-3.39)

Anthropometric data were available for 349 participants of a subsample of 360 children and their nutritional status could be determined thereon using the WHO's MGRS standard. Rate of malnutrition was 24.4% and analysis revealed that the nutritional status as well as gender failed to influence the AEFIs significantly (table-4).

Table-4: Distribution of participants as per AE developed within 28 days after vaccination & gender and nutritional status
Attribute AEFI+ve No. (%) AEFI-ve No. (%) Total No. (%) χ2 ,p values at df 1
Gender
[N=712]
Male 159(43.4) 207(56.6) 366(100.0) χ2=0.45,p>0.05
Female 159(46.0) 187(54.0) 346(100.0)
Status
Nutritional
Normal 145(54.9) 119(45.1) 264(100.0) χ2=0.79,p>0.05
Undernouris 42(49.4) 43(50.6) 85(100.0)

Both general systemic and specific systemic reactions were reported to be signicantly more in the lowest age group and also on 3rd month's follow up and declined over time with increasing age, being minimum on 1 year's visit (figure: 1 & table-5).

Distribution of vaccinees as per therir reported halth problem during 3 months through 1 year follow up
Fig-1:
Distribution of vaccinees as per therir reported halth problem during 3 months through 1 year follow up
Table-5: Distribution of vaccinees reported health problems over time during 3 months through 1 year follow up
Follow
up
1-5
vrsini=241]
6-
10vrsin2=231
11-
15vrsin3=2321
Total
[N=7121
χ2 for trend, p
3 88(36.5) 64(26.8) 63(27.2) 215(30.2) 4.377, 0.03643
6 55(22.8) 37(25.5) 29(12.5) 121(16.9) 1.012, 0.31445
9 50(20.7) 24(10.1) 21(9.1) 95(13.3) 13.966, 0.00019
1 yr. 32(13.3) 27(11.3) 16(6.9) 75(10.5) 5.019, 0.02507

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