[medlegiap] Re: MMR mass vaccination programme

In mathematical modelling in epidemiology, there is a critical threshold
value (denoted *qc*) at which enough people are immune to the disease that
its spread through the population (even to unvaccinated susceptible
individuals) is stopped. This effect is commonly known as herd immunity. If
a vaccination program does not attain *qc*, its effect is not to prevent the
spread of the disease across the unvaccinated population; instead it delays
the spread and so increases the average age at which individuals are
infected. This is called an *epidemiological shift*. In a disease
like rubella, which has an increased severity or risk of complications with
increased age, a vaccination program that causes an epidemiological shift
can in some cases have the unintended consequence of increasing the number
of deaths and problems caused by the disease, even if it protects vaccinated
individuals. Perverse effects arose in congenital rubella syndrome (CRS)
cases in Greece following the introduction in 1975 of rubella vaccination
for young children (BMJ 1999;319:1462-7). The resulting epidemiological
shift caused rubella to infect more pregnant women and cause more CRS,
showing that rubella vaccination programs should not be halfhearted.
Therefore unless swift and complete coverage of the population including
adolescents can be achieved, the vaccination program can cause increase in
incidence of CRS.


Dr Deepak Chawla
MD (Pediatrics), DM (Neonatology)
Assistant Professor
Department of Pediatrics
Government Medical College and Hospital
Sector 32
Chandigarh 160 030
India
Contact (O): +91-172-2665545-49, 2665253-60, Extension 2503
Fax: +91-172-2608488
drdeepakchawla@xxxxxxxxxxx, drdeepak.chawla@xxxxxxxxx


On Sun, Apr 12, 2009 at 8:54 AM, Blog coordinator <jhpedicon08@xxxxxxxxx>wrote:

>  A MESSAGE POSTED BY DR. UMA KIREETI FOR YOUR ERSPONSE. PLEASE FEEL FREE
> TO RESPOND AT WILL
>
> Dear Sir/Madam,
>
> Is it feasible to the IAP to recommend to the Government to launch mass MMR
> immunisation programme in order to prevent congenital rubella syndrome,
> there by decreasing the incidence of Congenital heart diseases ? One more
> thing I would like to know-how much % of CHDs are secondary to Cong.rubella
> syndrome? Kindly respond to my query. uma kireeti ukireeti@xxxxxxxxxxx
>

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