This does not happen with the injected vaccine, which contains a form of the virus that is essentially dead and cannot replicate at all. As a result, many countries have switched to injectable polio vaccines — the UK moved away from oral polio vaccination in 2004, for example. The injected vaccine is given in four or five doses, the first at the age of two months.
How did he get here?
So why is the virus in London’s sewage? The chain of transmission probably started with a child—someone who had recently been vaccinated with an oral vaccine in another country, Stonehouse says. “That child may be perfectly fine and may have stopped producing vaccine-induced polio by now,” she says. “But they may have passed it on to someone else, who passed it on to someone else.” The virus appears to have spread to a small but unknown number of people in London.
I say London because the virus was detected there. Sewage is routinely checked for a range of viruses at several sites there and one in Scotland, Stonehouse says. But many virologists think the virus could be spreading more widely in the UK and beyond – it’s just that we haven’t looked into it.
Why now? Stonehouse describes it as “bad luck”. It’s possible that this kind of spread happened before, and we just didn’t notice it. That’s no reason to be rude, though. “The virus spreads so easily that any indication of transmission is really worrying,” she says.
How worried should we be? Adults can develop severe disease, but this is rare, and they should still be protected by vaccinations they received as children. I feel grateful for the vaccine dosed sugar I was fed as a child.
Children under the age of five are at the highest risk of polio and its complications, so it is important to ensure that children are up to date with their routine vaccinations. My daughter already needs to be protected – she has already received three doses recommended for a child her age.
Children are more likely to contract and transmit poliovirus than adults, and they can do so even if they have received the injected vaccine. A statement from the UK’s Joint Committee on Vaccination and Immunization (JCVI) cited unpublished evidence that The whooping cough vaccine given to pregnant women can reduce their babies’ immune response to the first vaccinations, suggesting that these vaccines may not be as protective early in life. This is why even vaccinated children like mine are now offered the vaccine. And because the vaccine is so safe, “even if you’re fully covered, it won’t hurt to get another one,” says Stonehouse.
Polio cannot be cured, but it can be prevented. Which is why I packed my daughter, along with toddler-friendly biscuits and ready-made YouTube Cocomelon video on my phone, at our local doctor on a sunny Thursday afternoon.
My eldest daughter was not invited for a booster dose – vaccines are not offered to children who have received the preschool vaccine (at three years and four months) within the last year. But she will be eligible in a few months. I hope we won’t need it by then.