Vaccines straining to keep up with viruses

The African Horse Sickness Trust has dismissed a claim by DA spokesperson for agriculture, Annette Steyn, that vaccines produced by state-run Onderstepoort Biological Products, (OBP) for the deadly African horse sickness (AHS), are ineffective.

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Douglas Welsh, CEO of the AHS Trust, told Farmer’s Weekly that the vaccine was effective. This was confirmed by OBP’s business development officer, Dr Jacob Modumo, who said that it had received no complaints about the vaccine’s efficacy. “Like any vaccine the AHS vaccine is not 100% effective, but our records show that only 30% of vaccinated horses die as a result of contracting AHS. More than 90% of horses not vaccinated die after contracting the disease,” said Welsh.

He added that the vaccine was expensive and difficult to administer, putting it out of reach of poorer farmers in isolated rural areas.
Welsh felt that availability during periods of high demand was a bigger concern. “The AHS trust aims to vaccinate between 2 500 and 3 000 horses in an annual campaign targeting horses in poor, rural areas. “Last year, when almost 1 000 horses died of AHS, we identified at least 4 000 horses requiring vaccination, but there was no vaccine available,” he said.

The vaccine is usually administered during the low vector activity period from August to October. Despite OPB’s indication that vaccine was available for the coming season, Welsh said they would probably run out again if an outbreak triggered a high demand.
Dr Modumo said that the AHS vaccine had been out of stock for a week last year. He added that OBP now had sufficient stock.

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Steyn, a member of parliament’s Portfolio Committee for Agriculture, Forestry and Fisheries, recently drew attention to the deficiency of state-produced vaccines for Rift Valley fever (RVF). She has requested an investigation by the National Consumer Commission into potential breaches of the Consumer Protection Act (2008) by OBP with respect to vaccines for RVF and AHS.

Steyn said she would write to agricultural minister, Tina Joemat-Pettersson, to call for steps to be taken to ensure that OBP vaccines were subjected to testing by an independent oversight body such as the South African Bureau of Standards. OBP is currently accredited by SABS and the ISO.