Gaby Hinsliff’s piece (Anti-vaxxers are taking populism into deadly territory, 27 April) starts with a scenario from Pakistan where two vaccination workers are killed. Anti-vaxxers have caused people to question the safety of vaccination by spreading false information. However, as the Guardian has reported, the CIA did its part to make people distrust those working to vaccinate the population (CIA ran fake vaccination programme to snare Bin Laden, 12 July 2011).

Robert Kinzie

Kāne’ohe, Hawai’í, USA

• Thank you for your article (Five ways to strengthen your pelvic floor, G2, 6 May). Possibly the most memorable advice comes from doctor-turned-comedian Adam Kay, author of This is Going to Hurt: “There are leaflets that describe these exercises in confusing detail, but I always just used to tell patients, ‘Imagine you’re sitting in a bath full of eels and you don’t want any of them getting in.’”

Danielle Lowy

Manchester

• Your briefing on the European parliament (Journal, 6 May) failed to mention that such an institution was first proposed 326 years ago by William Penn, “for the peace and prosperity of Europe” (An essay towards the present and future peace of Europe, 1693).

Peter van den Dungen

Lightcliffe, West Yorkshire

• I’m hoping to have Light My Fire as I go into the flames (Letters, 7 May).

Monica Channell

Beckenham, London

• There have been black squirrels in Fairfield Park, Bedfordshire, for at least 10 years (Letters, 4 May).

Saul Ackroyd

Christow, Devon

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