As reported by other authors, the most relevant factor associated with a lower immunity rate was found to be increased age [3, 16, 17]. This finding is probably due to a combination of the lack of systematic vaccination before 1962, increased life expectancy and lack of administration of the recommended tetanus booster, the decline of tetanus protective antibody levels as age increases, and a deficient immune response to the vaccine which is associated with immunosenescence [15, 16, 18, 19, 20, 21].
These data confirm the fact that the elderly population is more at risk since they are less covered by the vaccine. We can therefore say that the analysed group of patients is representative of the Italian reality as described by the Italian Ministry of Health [17].
For what concerns the category of patients older than 60 years, it is possible to denote a difference among males and females in the immunization rates (Figure 2).
In particular, a slightly higher percentage of male patients of this class (12%) were protected against tetanus, with respect to female patients (3.7%). During the next years, in Italy, this finding could undergo a significant change, with a reduction in the difference between males and females aged 60 years or more. This, due to the fact that the Military Service is not obligatory anymore since 2005 [22], but also to the introduction of the obligatory vaccination schedule in 1968 [23], and to the more recent law [24, 25], which reaffirms that for the individuals of age comprised between 0-16 years old, a series of vaccinations have to be rendered mandatory and administered without charge. There will, therefore, be a greater homogeneity between elderly males and females.
Although the low prevalence of immunization among the elderly can be justified by the aforementioned historical reasons, a more unsettling finding is the one of younger people lacking protective antibody levels.
It is essential to focus on the fact that the vaccination against tetanus in Italy is currently mandatory at the age of 3 months, 5 months, 11 months, and 6 years in individuals born from 2001 on. A second booster dose is mandatory at 12-18 years for individuals born from 2001 on. Afterwards, Tdap (Tetanus Diphtheria and Pertussis) is recommended every 10 years from age 19, and also for pregnant women in the third trimester (ideally 28 weeks) [26, 27]. It is therefore astonishing that even the subset of patients aged 0 to 18 years has been partially found to be unprotected against tetanus infection.
The lower rates of protection present even among the younger patients might be due to factors such as a lack of knowledge about the importance of prevention of this disease through a complete cycle of vaccinations, as well as a lack of awareness on the necessity to receive boosters once completed the primary immunization series. This factor is probably a consequence of the fact that tetanus is currently one of the most underestimated and less well-known possible complications of a wound.
Another issue that could be important when considering high-risk groups populations is the one of immigration. Even though Pavia is not as cosmopolitan as other cities that have been taken into account by other studies, such as Rome and Brussels, the increase in the number of migrants from other countries in which the healthcare system is not so developed, may be partially responsible for the decrease in vaccination coverage over the next years. In this study, it was not possible to underline major discrepancies concerning the difference in immune coverage among patients of different nationalities, due to the small sample of foreign patients (34 units). However, this investigation could be an interesting topic on which to conduct subsequent researches.
In order to increase the prevalence of immunization among patients, prevention should be done, as suggested by the Ministerial Circular concerning the recent Decree Law [28], by promoting vaccinations both for newborns, and more aged patients who somehow did not complete the primary vaccination schedule. Better compliance with vaccine coverage has also been demonstrated to be associated with fewer hospital admissions in children [29].
Prevention should be done both through notifications under the form of letters, emails, leaflets, but also in a more direct way when the patient presents to the hospital or the cabinet of the general practitioner.
From a clinical point of view, this study underlines the importance of considering all individuals presenting to the Emergency Department with wounds at risk of contracting a tetanus infection. It is indeed demonstrated that most individuals in Italy, despite their age and gender, could be at risk of being not immunized against tetanus infection. It would be therefore important to either consult the patients’ vaccination card or, to assess their level of antibodies against tetanus through a rapid diagnostic test for the patients without a definite proof of a completed vaccination series.
The use of a rapid test would allow the detection of non-protected individuals, and it would help to choose the correct prophylaxis that has to be administered in the Emergency Department. Such a protocol, in the long run, would also help reduce the number of patients who are not protected against tetanus infection.
Patients should be made aware of the importance of keeping track of their immunization status, and of remembering the date of the last administration of the vaccine, especially in regions where rapid diagnostic tests are not available.
Moreover, it would be extremely important to more comprehensively educate patients on the topic of vaccines and vaccine-preventable infections, stressing on the fact that some of these infections could quickly lead to significant complications, and eventually result in the death of the individual.