BCG unsafe in some children

The practice of vaccinating all babies against Tuberculosis (TB), experts are now warning may not be appropriate, particularly in those with HIV and low immunity, reports Sade Oguntola.

Newborns are routinely given the Bacille Calmette-Guérin (BCG) vaccine in parts of the world where Tuberculosis(TB) is rife, such as Africa. The BCG was developed almost a century ago from a usually non-pathogenic, live strain of Mycobacterium bovis – the cow form of the bacterium that causes TB. Vaccinating children against TB is supposed to save lives from the growing threat of TB and the drug-resistant forms of this bacterial infection that commonly attacks the lungs and is becoming increasingly common worldwide.

This vaccine administered to millions of infants in developing nations in Africa and Asia in their first few hours of life, an expert in TB, Dr. Shehu Labaran , Assistant Director at the National Tuberculosis and Leprosy Control Programme office in Abuja, said is to make the child develop immunity against the infection.

Unfortunately, he said that aside BCG not being protective after five years of age when the immunity would have waned, it is also one vaccine that many infants born with HIV or with weakened immune system should not take. This weakened condition makes them vulnerable to “BCG disease”, a serious illness caused by the M. bovis of the BCG vaccine, which would otherwise not pose a threat.

“Talking about the safety of BCG in new born children, he said, “it is established that for those under five years of age, it is protective as long as the vaccine is potent. But as the years of the child increases, the protection starts to wane.

After five years, you cannot guarantee the protection and so after 5 years, the child can develop TB disease, “ Dr. Laban said.

“However, the use of BCG is not appropriate in persons with HIV. Because you are given the attenuated form of the bacilli which can turn out to be more infectious in those children with lower immunity. That is the reason that during antenatal care, they are supposed to have been screened and those found to be HIV positive followed up appropriately. Such babies when delivered are at risk of HIV until proven otherwise and so such should not be given BCG”.

Dr. Betrand Odume, a programme officer with the National Tuberculosis and Leprosy Control Programme office in Abuja, also explained that basically, TB in a place is TB everywhere, adding that all individual are exposed to TB germs and so the germ can become either dormant or infectious TB.

He said, “What determines what happens is the person’s immunity status”. Several factors can make a TB that is buried become infective and these include factors such as liver disease, kidney problem, diabetes, steroids, chronic use of alcohol and even malnutrition” the expert declared.

According to him, increasing cases of HIV is making for a rethink even with BCG usage in the protection of babies against TB.

One recent study conducted in South Africa and published in the journal, Clinical Infectious Diseases, found that six out of the eight children that became severely ill from the BCG vaccine ultimately died from the M. bovis infection. The majority of these children were found to have had HIV.

The World Health Organisation (WHO), had previously recommended that the BCG vaccine be given to all healthy infants as soon as possible after birth. However, the WHO revised its position and stated in a May 2007 report that "recent evidence shows that children who were HIV-infected when vaccinated with BCG at birth, and who later developed AIDS, were at increased risk of developing BCG disease."

The report said that, "among these children, the benefits of potentially preventing severe TB are outweighed by the risks associated with the use of BCG vaccine."

Currently, the challenge is to develop more sophisticated HIV tests for newborns because the types of HIV tests commonly used in the developing world cannot distinguish the HIV status of infants until they reach about six months of age.

Meanwhile, several factors make children with HIV more exposed to contracting the germ that causes TB and if they should get infected, increases their risk of dying by more than 50 per cent.

According to Dr. Odume, these factors include poor ventilation, unhygienic environment, crowded environment, poverty and lower body immunity due to malnutrition.

He explained that the TB germ spreads through the air when a person who has the disease talks, coughs, or sneezes and so when the environment is poorly ventilated and there is not much sunlight entering the room, the germ tends to thrive better.

However he said, HIV positive people can be made to have preventive TB treatment once they have been confirmed not to have TB.

In the case of children, Dr. Odume said their risk of exposure depends on them being in a place that has someone with the lung TB, their duration of stay in such a place and so on. “This is one reason mothers with such babies are advised to keep them away from places where people may be coughing or in poorly ventilated and aerated environment to further protect such children, ” he said.

Dr. Odume made case for the development of better vaccines that can protect all children from TB, irrespective of their immunity status.

Considering that TB and HIV are twin diseases of great importance that need to be controlled simultaneously for the battle to be won, Mr. Ben Nwobi, the National coordinator of NTBLCP, Abuja, said there is no doubt that Nigeria, like every other country, will have to consider the safety of BCG in children with lowered immunity.

“We will have to look at it and take a definite position. It is an issue that require a policy statement and policy guidelines on what should be done, “ he stated.

However, Dr. Hussein Abdur-Razzaq, the Lagos state Tuberculosis and Leprosy control officer said that much as the BCG vaccine cannot completely prevent an individual having TB later in life but ensure that the disease does not become severe, he assured that letting children have it still remains the best option.

According to him, “even if the child has TB, it particularly protects such a child against Tuberculosis meningitis, a severe form of TB seen in all age groups. This is a disease that is not diagnosed quickly and so may be very fatal”.

Many experts are however of the opinion that the search for more effective tuberculosis vaccines could produce novel options that avoid the problem of BCG-related illness. For instance, scientists are busy designing TB vaccines that are injection of proteins, as opposed to live bacteria, which would not pose as great a threat to children with HIV.

While it is important that TB vaccination continues, Veronica Miller, a co-author of a report on tuberculosis jeopardising the lives of HIV-infected children and director of the Washington, DC-based Forum for Collaborative HIV Research, said that there is an "urgent" need for changes to vaccination programmes in sub-Saharan Africa, including improved testing to know whether infants have HIV before vaccinating them against TB.