BCG vaccine causing disease in HIV-positive children

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BCG vaccination against tuberculosis can cause local or systemic disease in HIV-positive children, and doctors should be more vigilant for signs of complications associated with the vaccine, South African researchers reported last week at the 36th World Conference on Lung Health in Paris.

The BCG vaccine is given routinely to infants in settings where TB is endemic and is recommended for HIV-positive children in South African treatment guidelines. However, HIV-positive children appear to be at higher risk of complications, and researchers from the Desmond Tutu TB Centre at Stellenbosch University conducted a restrospective review of children at Tygerberg children’s hospital to assess the frequency of BCG-related illness.

They found that 25 children had been diagnosed with BCG disease after vaccination, of whom 17 were HIV-positive and a further two immunosuppressed for other reasons. Eight cases of systemic BCG disease occurred, all in immunosuppressed or HIV-positive infants, and six of the children with systemic disease died.

Glossary

systemic

Acting throughout the body rather than in just one part of the body.

 

culture

In a bacteria culture test, a sample of urine, blood, sputum or another substance is taken from the patient. The cells are put in a specific environment in a laboratory to encourage cell growth and to allow the specific type of bacteria to be identified. Culture can be used to identify the TB bacteria, but is a more complex, slow and expensive method than others.

abdomen

The part of the body below the chest, including the stomach, liver, intestines, kidneys, bladder, ovaries and uterus. The word ‘abdominal’ relates to pain or other problems in that area.

isoniazid

An antibiotic that works by stopping the growth of bacteria. It is used with other medications to treat active tuberculosis (TB) infections, and on its own to prevent active TB in people who may be infected with the bacteria without showing any symptoms (latent TB). 

gastrointestinal (GI) symptoms

Relating to or affecting the gut, stomach or bowel. GI symptoms include diarrhoea, abdominal pain (cramps), constipation, gas in the gastrointestinal tract, nausea, vomiting and GI bleeding. Among several possible causes of GI symptoms are infections and antiretroviral medicines.

 

The researchers warn that BCG disease should be suspected in all HIV-positive children, and in infants under the age of two, who develop palpable glands.

If systemic disease is suspected, they recommend a diagnostic workup that includes chest X-ray, gastric lavage for mycobacterial culture even if the patient is not febrile, intra-abdominal ultrasound if available to detect possible abdominal lymphadenopathy, and bone marrow aspirate for mycobacterial culture.

In HIV-positive children local or systemic disease should be treated with a four drug TB regimen of isoniazid, rifampicin, ethambutol, pyrazinamide, and ciprofloxacin or ofloxacin. If lymph nodes are swollen, fine needle aspiration should be considered, and if there is no improvement of severely swollen nodes after six weeks, surgical removal of the node should be considered.

Antiretroviral therapy can be considered in infants with systemic disease, but it is important to select a regimen that is compatible with TB drugs and which will not cause gastrointestinal upsets that might affect TB drug absorption. Baseline liver function tests to monitor for drug toxicity should be carried out in all infants with suspected BCG disease, the researchers recommend.

Although BCG disease seems to occur at a low frequency, it is difficult to treat and has a high rate of mortality. The researchers say that greater vigilance is needed to spot cases, but that BCG vaccination continues to be justified in HIV-positive children since it confers a degree of protection against tuberculosis in a high-risk group for development of the disease.

References

Hesseling AC et al. Danish strain BCG disease in HIV-infected infants. Int J Tuberculosis Lung Dis 9 (11, sup 1): S57, 2005.

Hesseling AC et al. Danish Bacille Calmette-Guerin vaccine-induced disease in human immunodeficiency virus-infected children. Clin Inf Dis 37: 1226-1233, 2003.