Cases of tuberculosis have struck at least three preschools since August last year.
Will my kid get it, too? Why wasn’t the school closed to prevent its spread? These were some questions raised by concerned parents when tuberculosis (TB) made an appearance in several preschools here recently.
In March, for instance, a staff member at a PAP Community Foundation Sparkletots preschool in Clementi was diagnosed with the disease. The other two cases, which occurred in August last year, affected teachers.
For parents, such incidents are worrying. Misconceptions about the infectious disease, such as how it is spread, may further fuel fear and anxiety.
Here, Young Parents gets the experts to lift the fog on TB.
A cold or flu is more contagious.
TB is an airborne infection caused by the bacterium known as mycobacterium tuberculosis, which means that it can be spread through air. But it is “much less contagious” than a viral infection such as the flu or a cold, says Dr Cynthia Chee, senior consultant at the Tuberculosis Control Unit at Tan Tock Seng Hospital, which sees about three quarters of all TB cases in Singapore.
“Only people with active TB, who are coughing out germs into the air, are infectious to others,” she adds.
She explains that TB is typically spread when the bacteria is breathed in by people who are in close and prolonged contact with the infectious person – we’re talking about days to weeks, rather than minutes to hours of exposure.
“It is not spread by contact with items or surfaces that the person has touched, sharing of toys, books, utensils and using the same washroom. And not everyone who is exposed will be infected as the body’s immune system, in most cases, is able to defend itself against the germ,” says Dr Chee.
It is not as common as you think it is in kids.
Only a small proportion of TB cases occurs in children, says Dr Chee. Last year, children and teens under the age of 15 years old made up 1 per cent of TB cases among Singapore residents, according to figures from the TB Control Unit.
“There has not been an increase in the number of cases at preschools or schools in the last 10 years. Given that TB is fairly common in Singapore, it is likely that occasional cases will occur in various settings,” says Dr Chee.
Children are at the highest risk of getting TB when someone in their household has active TB, says Associate Professor Thoon Koh Cheng, head and senior consultant at Infectious Disease Service, Department of Paediatrics at KKH Women’s and Children’s Hospital (KKH).
Other children at risk are those who have had an organ transplant or are on medication that suppress their immune system.
Most people have a form that is not infectious.
Nine in 10 people who are infected and have a healthy immune system will remain well throughout their lifetime, says Dr Chee.
This is known as “latent TB infection”, whereby the body’s immune system is able to hold the bacteria in a state of containment – the person does not have symptoms and will not spread TB to others, she explains.
Of this latent TB group, one in 10 will develop active TB later in life. This is when they may experience symptoms such as prolonged cough, fever, weight loss and fatigue, Dr Chee says.
KKH’s Prof Thoon says certain health conditions like HIV infection, kidney failure that requires dialysis, and diabetes may cause the dormant (sleeping) TB germs to “awaken”.
Infected kids under the age of five are at a greater risk than adults of progressing to active TB and getting more severe forms. For kids who did not undergo the Bacillus Calmette-Guerin (BCG) vaccination, this risk may be as high as 30 per cent, says Dr Chee.
It doesn’t only affect the lungs.
The most common organ affected by TB are the lungs, but the disease can also affect other parts of the body including the brain, spine and eyes.
For example, if TB affects the brain, the child may get seizures and/or weakness or paralysis of the limbs.
The BCG jab helps protect against very severe cases, but does not provide complete immunity.
Remember that BCG jab your baby received at birth?
The vaccination is meant to protect babies and young children against very serious forms of the disease, such as TB meningitis (TB of the brain lining), say the experts. But your kid can still get other forms of TB after his jab.
While the BCG vaccination provides some protection against lung TB, the protection is “incomplete” and lung TB can still occur, says Dr Chee. The World Health Organization also does not recommend a booster BCG shot because studies have failed to show benefits, she adds.
You are not infectious after two weeks of treatment.
A common misconception is that an infected person can easily spread the disease while on treatment.
Patients are considered not infectious after two weeks of treatment, shares Dr Chee.
She explains that there is no need to close places where an active TB case has been found. For one thing, unlike certain infectious diseases like hand, foot and mouth disease, TB germs cannot be passed through objects or surfaces. Early detection and treatment through screening of the patient’s close contacts can help prevent its spread.
“As patients would be on medical leave and started on treatment, there would be no risk of further exposure to workplace contacts once the diagnosis is made. Workplace or classmate contacts found to have latent TB infection are also not infectious,” says Dr Chee.
With early detection and treatment, it is usually curable.
It is important to detect and treat the condition early.
Current treatment is effective in curing TB as long as your child takes the whole course of medication. Treatment for TB usually lasts at least six months, with some cases stretching to nine months, says Dr Chee.
In Singapore, patients with active TB under the National TB Programme undergo Directly Observed Therapy, whereby the medication is given under supervision at your home’s nearest polyclinic.
