Transcript Rubella - An-Najah National University
An-Najah 2
nd
Medical International
“
Evidence based advances in women healthcare”
Conference
8-10/10/2009 Nablus- Palestine
Rubella immune status of Palestinian women.
study of more than 870 ladies tested for Rubella IgG in the period 2002 and 2009
Dr. Bashar Adnan Karmi Medicare-MediPal laboratories
MD, MSC Clinical Pathologist Immunologist/Microbiologist
History
• • • • The name rubella is derived from Latin, meaning “little red” Rubella was initially considered to be a variant of measles or scarlet fever and was called “third disease.” In1814 Rubella was first described as separate disease in the German medical literature, hence the common name “German measles.”
About rubella virus
• • • • First isolated in 1962 by Parkman and Weller.
Classified as a toga virus, genus Rubivirus.
Most closely related to group A arboviruses,
It is an enveloped RNA virus, with a single antigenic type that does not cross-react with other members of the toga virus group.
Following a widespread epidemic of rubella infection in 1940 Norman Gregg, Australian ophthalmologist, reported in 1941 the occurrence of congenital cataracts among 78 infants born following maternal rubella infection in early pregnancy. •
This was the first reported recognition of congenital rubella syndrome (CRS)
Maintenance of long-term antibody responses •
Is critical for protective immunity.
About rubella vaccine
About rubella vaccine
About the vaccine
The single component live attenuated vaccines of measles, mumps, • and rubella have been licensed in the USA since the 1960s • Combined live attenuated measles, mumps and rubella (MMR) vaccine was introduced in the United States in the 1970s • • •
In total, • over 90 countries around the world use MMR including our Palestine.
The RA 27/3 strain is used most often because 1) it gives consistent immunogenicity • 2) has low rate of side effects.
The role of MMR in reducing the incidence of these three diseases is agreed upon.
The vaccine used in Palestine
• • • Is TRIMOVAX from Sanofi Pasteur. Contains WHO approved Wistar RA 27/3M strain cultivated in human diploid cells.
Each dose contains at least 1000 C ell C ulture I nfectious D ose 50% ( CCID ).
Currently according to MoH
• • • • MMR is given in two dosages at age of 12 and 18 months.
A third boosting dose is given to girls in 6 th class.
The coverage is nearly 100% Since 1995 no registered CRS in Palestine.
As we have no data regarding the immune status for rubella, the aim of our Cohort retrospective study To assess 1) the % of rubella susceptible of age bearing women in Palestinian community.
2) efficiency of used vaccine vaccination program.
• 3) subsequently the need for including rubella test as a routine test for pregnant ladies in their first pregnancies.
•
Samples
• • • • Samples were obtained from ladies attending Medicare MediPal laboratories in Ramallah, Nablus, Hebron, Jericho and Al Eizaria cities. Usually this was part of their pregnancy follow up.
Serum samples was taken for rubella IgG and other ordered tests.
Tests were done the same day or the day after.
Method used
• The method used in Medicare- Medipal • is the Abbott FDA approved AxSYM method which uses the Micro-particle Enzyme Immunoassay (MEIA) for qualitative and quantitative measurement of IgG antibodies to rubella virus in human serum or plasma.
Hemagglutination Inhibition (HIA)
• • Is often referred as the reference method.
Since 1980, rubella virus IgG assays have been calibrated against the same WHO international standard rubella virus serum (second St. preparation) and test results reported in IU/ml.
Results
• • According to Abbott manufacturers, the presence of at least 10 International Units of antibody/ ml of sample is indicative of post exposure to rubella virus.
Antibody levels below 10 IU/ml may be insufficient to provide protection from clinical illness.
Initial Relative Sensitivity
• • MEIA method used in AxSYM Abbott showed 99.5% (1082/1088) sensitivity The 95% CI 98.8%-99.8%
Initial Relative Specificity
• • MEIA method used in AxSYM Abbott showed 90.8% (316/348) specificity The 95% CI 87.3%-93.6%
Number of tested subjects 2002-2009
Year Number tested
2002 2003 2004 2005 2006 2007 2008 2009 TOTAL 22 19 44 78 57 92 287 277 876
Immunity status of tested subjects
Year 2002 2003 2004 2005 2006 2007 2008 2009 Total % <5 IU /ml 5 2 1 0 3 1 2 7 21 2.5
6-9 IU /ml 4 2 0 1 0 1 3 6 17 1.9
> 10 IU /ml 21 18 41 69 53 90 282 264 838 95.6
No. tested 22 19 44 78 57 92 287 277 876 100%
WHO Literature accepts
• • • • Approximately 5% of vaccenees Not responding to vaccination ( negative sero conversion) and will develop No ANTIBODIES to Rubella virus. This is due to: 1) concurrent infection or to a 2) low level of pre-existing antibodies.
Age distribution of tested females Age/ years 15-19 20-24 25-29 30-34 35-39 40-44 45-49 total 0-5 IU/ml 0 5 6 5 2 1 0 19 6-9 IU/ml 5 9 7 5 1 0 0 27 ≥ 10 IU/ml 59 288 239 146 59 9 1 801 Sub total 64 302 252 156 62 10 1 847 % 12.4
39.9
26.8
14.2
6.1
0.5
0.1
100
Age-Specific Fertility Rates and Total Fertility Rates by Region-1995 (PCBS)
Age Group 15-19 20-24 25-29 30-34 35-39 40-44 45-49 Total Fertility Rate (TFR) West Bank 100 273 264 229 155 62 5 5.44
Gaza Strip 144 340 347 289 230 123 5 7.41
Total 114 294 291 248 177 82 5 6.06
Dose Rubella IgG levels change with age?
• Do we have deferent IgG levels with different women age groups?
Rubella IgG IU levels with age
IU IgG Level
0-1000 100-1000 50-99 10-49 0-9
Age 15-29 YEARS
646 196 202 208 27
%
100% 30.34
31.27
32.2
4.2
Age 30-49 YEARS
241 75 71 80 13
%
100% 31.12
29.46
33.2
5.4
Back to the aim of our study
1) Finding out the % of rubella susceptible of age bearing women in Palestinian community.
The answer is 4.4 % according to our findings
Back to the aim of our study
cont.
2) Efficiency of vaccination program • According to our findings, the vaccine • outcome consists with the expected results proposed by the manufacturers.
Back to the aim of our study cont.
3) Subsequently the need for including rubella test as a routine test for pregnant ladies in their first pregnancies.
We believe it is worth thinking of including rubella IgG as regular test in pregnant ladies • follow up.
•
Conclusions and Recommendations According to our results: 1) 4.4 % of Palestinian age bearing women are Rubella susceptible.
2) The above figures consists with data from international research findings as well as with the expected outcome from the vaccine.
3) As the cost estimate of CRS is 200,000$ (USA figures) it might be recommended doing the rubella IgG test for all pregnant ladies in their first pregnancy and keeping the results in their files for following pregnancies.
4) It is rather better to conceder the lady as rubella susceptible when equivocal result is obtained.