“…The case-control study also allowed each risk factor to be adjusted for the effect of the others either in the same group or in the other sets of variables, achieving a better understanding of the interrelationships among each variable, the outcome and additional factors, minimizing the problem of confounding factors among the variables studied. Third, finally, because this study has not only ratified the importance of certain factors already recognized in the literature as being important in determining the tetanus patient's prognosis (age 11 , short incubation and progression periods of onset 1,3,4,5,6,16,17 , presence of spasms in the first 24 hours 1 ), but also pointed out other prognostic indicators as yet little used (time elapsed between onset of symptoms and admission to hospital 1 ) or even unmentioned in the literature consulted (occurrence of neck stiffness in the first 24 hours and the occurrence of respiratory signs and symptoms in the first 24 hours of hospitalization, such as the presence of at least one of the following: tachypnea, dyspnea, attacks of apnea, rhonchi or respiratory crepitations, cyanosis, cough, bronchial spasms, pleuritic pain).…”