Have you ever wondered why there is not an effective vaccine against tuberculosis (TB), a disease that kills one and half million people each and every year? Or why having an episode of TB does not give protection against a new infection like other diseases such a measles? The answer lies in the fact that TB is an ancient disease and the bacterium (Mycobacterium tuberculosis) has, over the millennia, evolved clever ways of evading the human immune system.

Where are you at the moment? I’m in the city of Recife, on the eastern tip of Brazil. It’s the capital of Pernambuco, the state at the centre of the Zika epidemic. Was anyone prepared for this?

Zika has caught the world by surprise. The declaration by the World Health Organization that the recent cluster of microcephaly cases and other neurological disorders constitutes a Public Health Emergency of International Concern, shows the seriousness of the situation. The virus is transmitted by Aedes aegypti mosquitoes. Vector control should be, and is, the focus for stopping the spread of Zika. But will current control methods work?

Tuberculosis (TB) has been known to mankind since ancient times, and is likely to have caused more deaths in human history than any other infectious disease. Unlike HIV and malaria, globally rates of disease are falling very slowly and last year it once more became the leading cause of death due to a single infectious disease, causing 1.5 million deaths every year. Despite its importance, there is great uncertainty about the transmission of M.tb (the infection causing TB disease) – where it happens and who infects whom.

Babies born in poor countries can be 50 times more likely to die in their first month of life than babies born in rich countries. In the safest country in the world for newborns, Japan, 1 of every 1000 newborn babies die in their first four weeks of life. In the United Kingdom, 3 of every 1000 newborn babies die. But in Sierra Leone, the most dangerous country for newborns, 50 of every 1000 newborn babies die in their first month – one death for every 20 babies born.

The recent image of the body of a dead three-old boy on a Turkish beach seized the world’s attention and provoked the worst nightmare of parents everywhere. This photo, which warrants the international outrage it has received, sadly only hints at the full panorama of childhood horrors that occur around the world each day.

Year 8 schoolgirls in the UK (12-13 years old) receive two doses each of a vaccine against human papillomavirus (HPV), a virus that causes cervical cancer as well as genital warts and a number of other unpleasant cancers. Until 2013, they received three doses of the vaccine each.

I was disheartened to learn last week that the US Federal Drug Administration approved flibanserin for treatment of low female sexual desire. The decision was claimed as a victory for women. But as a researcher working in sexual dysfunction and interested in the medicalisation of sex, the victory tasted a little bitter.

Recent positive results from the Guinea Ebola vaccine trial, which suggested a vaccine could provide high protection against the virus, were welcome news. However, it’s also essential that we continue to carry out research to ensure Ebola patients are receiving appropriate care and effective treatment.