Pneumococcal vaccine works even in HIV patients


Trials of a vaccine against the most common cause of pneumonia and meningitis — both leading causes of death in HIV sufferers in Africa — have proved so successful that scientists say it could be a major breakthrough in combating the diseases.


The new vaccine protects against Streptococcus pneumoniae which causes pneumonia and, when it invades the bloodstream and brain, causes septicaemia and meningitis.

Adults in the United Kingdom and the United States are given a polysaccharide vaccine but, because it does not work well in HIV-infected adults, it is not recommended in Africa.

The new conjugate vaccine was tested using nearly 500 HIV-infected adults who had recovered from a bout of pneumococcal disease. Three quarters of the patients remained free from the disease, according to the researchers at the Malawi-Liverpool-Wellcome Trust Clinical Research Programme, based at the University of Malawi College of Medicine.

The vaccine worked even when the number of CD4 cells in a patient's blood — an indicator of immune strength — was less than 200, the level that indicates AIDS.

Unlike the polysaccharide vaccine the new conjugate vaccine contains a protein that helps the body’s immune system recognise the pneumococcus bacteria, said Neil French, of the Liverpool School of Hygiene and Tropical Medicine, in the United Kingdom, lead author of the study.

"The general view on the use of any vaccine in HIV is that low CD4 counts make the vaccine useless. We've shown that conjugate technology overcomes the profound immune deficiency at these low counts. This gives hope for the possible use of conjugate technology in other vaccines targeting important HIV associated bacterial infections, most notably non-typhoidal Salmonella," he said.

"If conjugate vaccines are found to confer protection against invasive pneumococcal disease, this will be a major breakthrough, to reduce the morbidity and mortality of HIV infected persons from pneumococcal disease," said French.

Jeremiah Chakaya, a chest specialist at the Kenya Medical Research Institute welcomed the vaccine but said it will only be a breakthrough when the price — US$40 — is brought down.

"If the cost of the conjugate vaccine is about US$40 per dose, then it is going to be very difficult for most African governments to purchase it, and even if they do, then the people who need it will have to buy it at a very high price. This would make the vaccine a preserve of the few rich people in the countries."

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WEST AFRICA: Rice versus vegetables

 Rice may still be a symbol of food security across Africa, [http://www.irinnews.org/Report.aspx?ReportId=88564] but the cereal does little to boost nutrition, unlike vegetables, according to the India-based International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).


Vegetables should have their place in the fields and at the table alongside cereals commonly grown in arid countries, vegetable breeding expert Sanjeet Kumar with ICRISAT and the Taiwan-based AVRDC-The World Vegetable Center (formerly known as the Asian Vegetable Research and Development Center) told IRIN.

"While rice and other cereals can cut hunger, vegetables bolster nutritional security and take up less land to grow."

"Rice is a poor source of essential vitamins and minerals, either because these compounds are not present in rice, especially when it is polished [white], or they cannot be absorbed by humans," UN Children's Fund (UNICEF) nutrition specialist Roland Kupka told IRIN. "Diets that are primarily based on polished rice may thus lead to deficiencies in iron, zinc, vitamin A, and thiamine [B1] deficiency, which in turn impair growth, immunity, and mental development among children."

Mineral and vitamin-packed foods include fruit, vegetables and animal products like eggs or fish, said Kupka.

UNICEF estimates 40 percent of under-five children in the arid Sahel are chronically malnourished because they lack the vitamins and minerals needed to bolster their immune systems and mental skills. Another estimated 300,000 die every year from malnutrition.

While health workers may have scales, armbands and yardsticks to measure acute malnutrition (when children are underweight for their height), they are less likely to have microscopes to analyse blood work to measure micronutrient deficiencies.

When asked whether rice overshadows more nutritious agriculture sectors, the director of Africa Rice Centre, Papa Abdoulaye Seck, told IRIN that rice cultivation can subsidize these other crops.

"Rice is a strategic commodity. We can do business with rice. Imagine if the US$2 billion dollars [2006 estimate] that Africa spends on rice imports every year were reinvested in the agricultural sector - do you think Africa would now have 265 million starving people?" asked Seck, referring to an estimate from UN Food and Agriculture Organization (FAO).

Seck said farmers in Africa have a comparative advantage in growing rice. "We want to develop rice instead of [only] vegetable gardening, because Asia, the largest producer of rice, will not be able to continue doing so. In Asia, there is arable land, but less water. While in Africa, we have enormous potential."

FAO estimates farmers use 17 percent of cultivable land in Africa, which leaves some 126 million hectares to plant, he said.

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