How HPV vaccine and circumcision can stop cervical cancer

Does a USB stick, or a mobile phone, weigh more once it's filled with data? What's the placebo effect, and how does it work? How does the human papilloma virus (HPV) cause disease, and how can the HPV vaccine and male circumcision protect you from cervical cancer and HIV? Does Cape Town face two oceans? Can Brazil nut proteins be present in semen and trigger subsequent anaphylaxis in a sexual partner? And what can we do about post-herpetic neuralgia causes by shingles (VZV)? Like this podcast? Please help us by supporting the Naked Scientists (https://www.thenakedscientists.com/donate)