What people know about congenital CMV: an analysis of a large heterogeneous population through a web-based survey

Our survey collected information regarding awareness of cCMV in a sizeable population with considerable heterogeneity of socio-demographic variables through a web-questionnaire. In Italy, as is the case in other countries, no data about cCMV awareness in general populations are available as yet. To our knowledge, the surveys published so far about this issue targeted specific population clusters such as pregnant women [6, 7], physicians [13], health care providers [9] and medical students [10].

In our study only about one third of the population inspected was aware that CMV can be congenitally transmitted although half of the participants had declared that they had heard of the virus and the factors associated with awareness of cCMV were womanhood, parenthood, people >24 years and Master’s degree holders.

Nevertheless, our population evinced hearing about cCMV more frequently than the one involved in a study carried out by Cannon et al., since in that study among 4,184 interviewees only the 10 % (13 % of women and the 7 % of men) stated a knowledge of cCMV [12]. This difference can be explained thanks to the high level of education of our respondents, given that almost all had, at least, achieved high school graduation. Moreover, cCMV prenatal screening has been relatively common in Italy whereas it is rare in the U.S.

As in others studies [6, 7, 14‐16], also in our research awareness of cCMV ranked second lowest (fetal alcohol syndrome is the least recognised) among a group of congenitally acquired conditions all of which have an incidence in the population lower than that of cCMV. A number of reasons could lie behind this finding: first, there is no CMV vaccine, in contrast to other preventable infections such as rubella and measles; second, cCMV infection is less discussed in the media than toxoplasmosis and HIV/AIDS; third, children with cCMV do not have characteristics symptoms and signs such as those found in Down syndrome or spina bifida and so are typically not diagnosed. Since only 1 baby in every 10 infected shows symptoms at birth [1], cCMV infection may have low emotional impact on the population.

In spite of cCMV being the most important infectious cause of paediatric deafness [17], only around half of our interviewees recognised sensorineural hearing loss as a sequela (at birth or as a later development) of the congenital infection, similar to another study [8, 12], and they believed that cCMV infection is symptomatic at birth. The low quality of knowledge in the whole population concerning viral outcomes confirms that although people had already heard of cCMV, the virus was considered to be of little danger and potential damage, similar to Willame et al. results [16].

In our survey, the questions regarding both the transmission routes and the suggested preventive behaviours computed the highest scores, suggesting a generally good health education that, however, is not specific for cCMV. In fact, when each answer is considered in detail, some findings have to be underlined. First, although more than half of individuals reported knowing that the infection can result from adult-to-adult transmission (such as via blood, sexual activity, transfusion/transplant), they were much less aware that children –in particular through urine-are involved in CMV infection, similar to others studies [6, 11, 12]. So, it can be assumed that our population failed to recognise CMV shedding from infected children, both congenitally and postnatally, and to realize that child-to-child and child-to-mother are the most common routes of viral transmission [18], especially when the child attends a day-care centre [19]. Consequently, among preventive measures that pregnant women should follow in order to avoid the infection, behaviours specifically concerning child contact were recognised by up to twenty percentage points lower than others items. Second, about a third of respondents thought that ‘avoiding eating rare cooked meat’, ‘changing the cat litter box with gloves’ and ‘avoiding animal contact’ were preventive behaviours against cCMV, mistaking CMV for Toxoplasma. Third, women, individuals of childbearing age and parents, believed, in percentages ranging from 35 to 45 %, that pregnant women are not at risk of infection if already immunized, thus providing further evidence that people do not know that CMV behaves differently from “conventional” infectious agents. In fact, the presence of CMV antibodies in the serum is often wrongly referred to as “immunity” (immunity being interpreted as protective). However, reinfection with CMV can occur in CMV seropositive people because the protection conferred by preconception immunity is limited to strains-dependent immune responses [20] and viral reactivation can take place since CMV can be latent in the host after primary infection [21].

Unexpectedly, women and parents did not show an increased degree of knowledge about cCMV in our study, probably due to being poorly informed. A number of studies have shown that physicians, obstetricians and health care providers are not familiar with cCMV transmission, prevention and management even if they are the main source of child and maternal health information [8, 9, 22]. In an earlier Italian survey, the proportion of puerpera declaring themselves to have received information about appropriate behaviours against cCMV was about 26 % in the ‘immune’ group vs the 49 % in the ‘non-immune’ (p < 0.000) (immune here referring to their CMV serological status) (Barbi M., et al., unpublished data). Considering an ‘immune’ woman safe from further CMV infections means giving her a false sense of security.

Moreover, some authors have reported a paucity of CMV information in pregnancy-related reference books and websites [23, 24]. This aspect should be investigated in more depth in future Italian studies.

The study was subject to several shortcomings. First, the response rate was 14.4 %. Despite this low rate, it represents more than 10,000 interviewees, hence, as far as we are aware, this is the largest survey ever carried out about cCMV awareness. Second, the survey was based on a convenience sample that, although used widely by researchers, can lead to biased results. Interviewees had an higher education level, were younger on average, and the gender distribution was skewed towards female in comparison to the general Italian population. In any case, this study does not focus on any particular group but on a population that is heterogeneous for gender, age, level of education and parenthood. Third, differences between respondents and non-respondents could have resulted in biased results. Even if we had no information on non-respondents, the declaration of a public health issue as the general topic in the email invitation leads us to suppose that respondents answered because they may have been more interested in health issues than non-respondents. This bias, therefore, might imply that the true awareness concerning cCMV is less than that reported above.

In conclusion our study highlights the poor, confused and insufficient quality and degree of awareness about cCMV in the considered population although it was conducted among individuals predominantly possessing a high level of education and being of childbearing age. As a consequence of our findings, we strongly believe that various actions have to be taken by public health policy-makers and these findings could be useful for determining both the most effective content for preventive messages and the most appropriate target populations; these actions include the following: all employees involved in child-mother care have to be adequately educated about cCMV so as to be able to share accurate information both on cCMV outcomes and on appropriate preventive behaviour. Health education programmes targeting cCMV should urgently address and remedy the problems revealed here and a media campaign should be launched to raise awareness.