The spasms can be triggered by anything from a sudden noise, movement, or draft of air to such internal stimuli as a full bladder or a cough. Fortunately, most people in industrialized countries needn't worry that everyday scratches and scrapes will yield an internal harvest of tetanus toxin. Because they've received a series of tetanus vaccines in childhood as well as the occasional tetanus booster, their bodies have plenty of protective antibodies. Reported tetanus cases in the United States often number no more than 100 a year. But people in the developing world are less likely to receive tetanus vaccines and they suffer the consequences.
Newborns are particularly vulnerable.
During the first few weeks of life, their only defense against pathogens comes from antibodies imported from their mothers' breast milk. Infants born to nonimmunized mothers are tetanus cases waiting to happen. One dirty knife or soiled bandage on the umbilical stump is all it takes. Today neonatal tetanus accounts for over half of the more than 500,000 cases worldwide. In my quick exam of Eduardo, I hadn't seen a scratch.