Cheaper treatment for diarrhoea, but pneumococcal vaccine useless in Africa

This article is more than 23 years old.

Two simplified, antibiotic regimens are effective in treating HIV-related diarrhoea, according to a study by US/Haitian researchers. The finding provides a cheaper treatment option for HIV-related diarrhoea in resource-poor settings.

A HIV clinic in Port au Prince, Haiti, found that 17% of HIV-infected individuals had chronic diarrhoea. The authors enrolled 42 individuals with chronic diarrhoea infected with either Isospora belli or Cyclosporia cayetanensis. On average, participants reported diarrhoea for over 4 months and 40% had lost more than 10% of their body weight.

Participants were randomised to either trimethoprim-sulfamethoxazole (TMP-SMX, 160/800 mg) or ciprofloxacin (500 mg) twice daily for seven days, followed by one tablet every second day to prevent recurrence of infection. Current standard treatment for isosporiasis and cyclosporiasis is TMP-SMX four times daily for 10 days, then twice daily for 3 weeks.

Glossary

diarrhoea

Abnormal bowel movements, characterised by loose, watery or frequent stools, three or more times a day.

pneumococcal disease

Disease caused by the bacterial infection Streptococcus pneumoniae. In most people, it causes relatively minor health problems (called ‘non-invasive’ infections) such as bronchitis, sinusitis (sinus inflammation) and middle-ear infections. It can also cause serious pneumococcal diseases including severe bacterial pneumonia, sepsis (blood poisoning) or meningitis (inflammation of the brain lining).

pneumonia

Any lung infection that causes inflammation. The infecting organism may be bacteria (such as Streptococcus pneumoniae), a virus (such as influenza), a fungus (such as Pneumocystis pneumonia or PCP) or something else. The disease is sometimes characterised by where the infection was acquired: in the community, in hospital or in a nursing home.

isosporiasis

Also known as cystoisosporiasis, an illness caused by the intestinal parasite Isospora belli (or cystoisospora belli).

relapse

The return of signs and symptoms of a disease after a patient has been free of those signs and symptoms. 

Diarrhoea ceased in all individuals on TMP-SMX and in 20/23 individuals taking ciprofloxacin. Seven of the ciprofloxacin group continued to have signs of infection, although all were successfully treated with TMP-SMX.

The authors concluded that a one-week course of TMP-SMX was effective in treating cyclosporiasis or isosporiasis, and that ciprofloxacin was an effective regimen among individuals intolerant to TMP-SMX. During the ten-week follow-up period, only one relapse was reported - in an individual who had taken ciprofloxacin.

However, a study published today in The Lancet suggests that the use of pneumococcal vaccine is a waste of money in sub-Saharan Africa, and may even lead to an increased risk of pneumonia. A randomised controlled trial in 1392 HIV-infected Ugandans found that cases of pneumonia occurred more frequently in those who received polyvalent pneumococcal vaccine of the type recommended in Europe and North America (p=0.008). The vaccine offered no protection against pneumococcal disease, and almost all cases of pneumonia in the vaccine recipients displayed isolates of S pneumoniae identical to those included in the vaccine.

The study was not powered to detect any interaction between vaccination, CD4 count and viral load on the incidence of illness, but there was no significant difference between the study arms in the incidence of other opportunistic illnesses. This suggests that the increased incidence of pneumonia was a direct effect of the vaccine rather than a consequence of stimulation of virus production and subsequent loss of immune competence.

References

French N et al. 23-valent pneumococcal polysaccharide vaccine in HIV-1 infected Ugandan adults: double-blind, randomised and placebo controlled trial. The Lancet 355: 2106-2111, 2000.

Verdier R-I et al. Trimethoprim-sulfamethoxazole compared with ciprofloxacin for treatment and prophylaxis of isospora belli and cyclospora cayetanensis infection in HIV-infected patients. Annals of Internal Medicine 132:885-888, 2000.