Thread by @dgurdasani1

The UKHSA has identified 116 isolates of type 2 polio virus (oral polio vaccine virus) in sewage samples from eight London Boroughs. The genetic analysis indicates that they're likely related to the virus imported in Feb, suggesting community transmission has been established 🧵

There have been no cases of associated paralysis, but this is worrying. The oral polio vaccine virus is a weakened virus- doesn't generally cause paralysis, but it can if given the chance (through community transmission & mutation) revert to higher virulence and cause paralysis

The current strain circulating seems to be the vaccine virus which was probably imported from someone who was given the oral vaccine abroad. The polio virus (and the vaccine polio virus) spread through wastewater/sewage & faecal transmission.

Unfortunately, there are signs that the usually benign vaccine virus is mutating into more virulent forms. The UKHSA report that a few cases of 'vaccine derived' polio virus have been detected. This virus is closer to the wild type and can cause serious illness & paralysis.

The reason we're seeing transmission of vaccine virus in the community is likely due to poor sanitation, and lower uptake of polio vaccine in recent years- particularly in England- and in England in parts of London.

England, and particularly parts of London are below the WHO target for polio vaccination in children- set at 95%. And this puts regions with lower vaccine uptake at risk of outbreaks, and community spread.

It's clear that community transmission has now been happening since Feb '22 when the first vaccine virus was detected in sewage. 6 months of transmission is giving the virus plenty of chance to mutate. We need to break this.

Better sanitation, hygiene, and vaccine catch-up are the best ways of doing this. Booster vaccines are now being offered to all 1-9 yr olds in affected areas. Please do take your child for these if they're invited.

Check their red book and contact your GP if they haven't had all their doses. Children are supposed to have 5 doses - 3 doses 4 wks apart in their first year of life, one before school (3 yrs 4 months), and one in teenage yrs (14 yrs). Make sure your child has had these.

The vaccine being given in the UK is not the oral polio vaccine that can spread and revert to higher virulence. It's an injectable vaccine of inactivated virus that poses no risk of transmission, so these are very safe.

I'm concerned about the increase in vaccine hesitancy and lowered uptake of vaccines we've been seeing in the UK during recent years (before everyone blames this on COVID, worth pointing out that drops in polio vaccine uptake predate COVID).

We need much stronger public health messaging around childhood vaccination - we've seen huge disinformation campaigns around COVID vaccination directed at parents. And anti-public health stances become more popular. It's important that these don't have knock on effects.

There's a level of complacency perhaps because the UK hasn't seen a huge burden of infectious diseases for a while (which may explain the failed response to COVID). Believe me, re-emergence of infectious disease that have been eliminated isn't something we want to see again.

With COVID and monkeypox, and re-emergence of several threats across the globe, it's important to act early and fast to break these chains of transmission as a matter of urgency- rather than wait for 6 months as community transmission gets established before acting...