May 27, 2009
Chicken pox no longer listed as notifiable disease
MOH regards virus as low risk because vaccine is available and complications are minimal
By Judith Tan
CHICKEN pox brings the misery of fever and itching but it is no longer considered a public health hazard and doctors will not need to report it anymore.
There are 44 diseases which must be reported to the Health Ministry (MOH) within 24 hours of someone becoming ill, and chicken pox is no longer one of them.
Notifying the ministry allows the health authorities to track cases and contain the spread of the disease.
Chikungunya was the latest to be added, at the end of last year, to a list which includes HIV/Aids, hand, foot and mouth disease, and dengue fever.
Chicken pox was delisted in January - the first to be removed from the National Notifiable Diseases in years.
A vaccine for varicella zoster, as the virus is known, has been available for more than 10 years.
Contracting chicken pox also makes one immune for life, though one remains at risk for the secondary infection, shingles.
The number of patients infected by chicken pox fell last year from 30,548 in 2007 to 27,200.
The fall is because of the vaccine.
'The risk to public health is therefore low and there has been no need for public health intervention,' said a ministry spokesman.
Chicken pox was recently in the news when Senior Minister Goh Chok Tong was infected and admitted to the Singapore General Hospital (SGH) earlier this month.
After he recovered, he advised adults who had not yet caught the childhood disease to get vaccinated. Chicken pox can lead to complications such as pneumonia, and throat and brain inflammation.
The chicken pox vaccine contains a weakened live form of the virus and is injected into a healthy person to build resistance to the disease and its complications.
Dr Chong Chia Yin, Head of Paediatric Medicine at KK Women's and Children's Hospital, said it should be given to any child above 12 months old, adults - especially women planning a family - and health-care workers.
Last year, National Healthcare Group polyclinics gave about 3,500 chicken pox vaccinations.
And in the first three months of this year, the ones at SingHealth gave more than 180 vaccinations to both adults and children.
The two-dose shots cost between $120 and $128.60 at the polyclinics.
They are not included in the National Childhood Immunisation Programme, which provides funding for vaccination against diseases which are high risks to public health.
'Only a small proportion of cases are hospitalised and death due to chicken pox is very low, the majority of them due to other complications,' an MOH spokesman said.
Dr Leong Hoe Nam, a consultant in infectious diseases at SGH, warned that there was a small risk of contracting chicken pox or shingles from the vaccination.
What you need to know
What is chicken pox?
Chicken pox is caused by the varicella zoster virus and is very contagious.
It usually infects children, but adults, if not infected as children, can also catch it.
The symptoms include itchy rash and mild fever. The rash, which appears on the face and body first, may begin as smooth, red spots but develops into blisters by the third to fourth day.
How is it spread?
Chicken pox is spread by direct contact with the fluid from broken chicken pox blisters or through the air by coughing or sneezing.
An infected person is contagious for one to two days before and shortly after the onset of a rash; and continues to be contagious for about five days until the lesions become crusted.
What is the chicken pox vaccine?
It contains a weakened form of the chicken pox virus and is injected into a healthy person to help build resistance to the disease and its complications.
Children between one and 12 years of age are usually given one dose, while adults and teens from 13 years of age need two, which are given six months apart.
Can you get chicken pox if you've been vaccinated?
As long as they have been vaccinated, fewer than 15 per cent may still get chicken pox if they are exposed, but the infection is usually mild.
What are some serious complications that can arise?
They include bacterial infections of tissues under the skin, bone, lungs, joints, and blood.
COMPLICATIONS from chicken pox have been found to be higher in adults and children who are not the first case in the family.
FIVE YEARS OLD AND YOUNGER:
Bacterial skin infection - 1:3,800
Pneumonia - 1:7,700
FIVE TO NINE YEARS OLD:
Encephalitis (inflammation of the brain) - 1:11,000
10 TO 14 YEARS OLD:
Encephalitis - 1:11,100
15 TO 19 YEARS OLD:
Encephalitis - 1:3,400
Varicella-zoster (VZ) pneumonia - 1:4,100
20 YEARS OLD AND OLDER:
Encephalitis - 1:3,000
VZ pneumonia - 1:375
The following people should not receive the varicella vaccine:
§ Anyone with a weakened immune system or who has serious illness
§ Anyone with serious allergies to gelatin or the antibiotic neomycin
§ Anyone who has had a severe allergic reaction to a prior dose of the drug
§ Pregnant women and those attempting to become pregnant, as the possible effects on foetal development are unknown
§ Those receiving high doses of steroids, such as prednisone
§ Those receiving treatment for cancer with X-rays, drugs or chemotherapy
§ Anyone who has received blood products during the past five months, such as blood transfusion