The Switch is here
During the last two weeks of April, the biggest ever undertaking in the field of public health has been taking place – The Switch.
The triple oral polio vaccine contains three live, but attenuated, viruses. The attenuation stops the virus mutating and becoming virulent again, but nothing in medicine is fool-proof and some cases of polio due to the vaccine have occurred because of this mutation. The virus that changes most often and cause nearly all the problems has been the Type 2 which has not been seen in the wild since 1999.
When there were 1000 cases of polio each day, the occasional case actually caused by the vaccine was, regrettably, an acceptable risk, but with only 11 cases in the whole world this year, that risk is totally unacceptable, so the Type 2 component has been removed. Hence all countries are changing together. If some do not, and continue to use the triple vaccine, there is a risk that more cases of Type 2 vaccine-derived polio could occur.
To mitigate that risk, all countries that still use the oral vaccine have also included at least one dose of injectable vaccine which contains a killed/inactive virus. In the UK, USA, Australia and a number of other countries, the oral vaccine has not been used for a number of years, just the injectable.
This has been a massive project with all the Polio Plus partners combining with an organisation called GAVI to finish the fight once and for all.
Report by Keith Barnard-Jones
To find out more about this amazing global project on the Rotary International Web site