It has been suggested that maternal helminth infection in pregnancy may have an adverse effect on the infant's immune system. However, a recent trial in Uganda (Lancet 2011;377:52–62) see also Comment, ibid: 6–8 has shown that anthelmintic treatment given to pregnant mothers in an area in which helminth infection is very common does not improve the infants responses to immunisation or reduce susceptibility to infection. A total of 2507 women were randomised in the second or third trimester to one of four single-dose treatments: albendazole 440 mg plus praziquantel 40 mg/kg, albendazole plus placebo, praziquantel plus placebo, or double placebo. Infant responses at 1 year to BCG (Bacillus Calmette-Guérin), tetanus and measles immunisations were similar in all four groups. Among the infants of hookworm-infected mothers albendazole reduced interleukin 5 and interleukin 13 responses to tetanus toxoid. Rates of malaria, diarrhoea and pneumonia were not affected by treatment with either albendazole or praziquantel and among HIV-infected mothers transmission of HIV from mother to child was not affected.

Around 40% of the world's children are exposed to secondhand tobacco smoke. A WHO-sponsored study (Lancet 2011;377:139–46; see also comment, ibid: 101–2) has provided estimates of the worldwide burden of disease in children and adults resulting from passive exposure to smoke. Data were collected from 192 countries. …