During the first waves of the COVID-19 pandemic, adults living with children faced particular difficulties and worries (1–3). On the one hand, they were concerned about children's health, mainly at the beginning of the pandemic, when there was still high uncertainty about the severity of the infection among them (4). On the other hand, they had specific worries related to the consequences that some public health control measures, such as lock-downs, social distance recommendations (5) or school closure (6) could have on children' physical and mental health (7), and on their development and education (8).

All these aspects may have influenced the attitudes and practices of this population group during the pandemic (2). They may have been more interested in learning about the COVID-19, its transmission mechanisms, and preventive measures, and, perhaps, they may have been more compliant with preventive measures, both to protect and to serve as an example for their children, as has been observed in other emergencies (9). It is known that parents are important socialization agents who play the role of health promoters, role models, and educators in the lives of their children (10) and, in this case, they were responsible for teaching and making their children follow the preventive measures established to reduce the risk of getting SARS-CoV-2 infection, modulating this way the capacity of protecting themselves. On the other hand, they might have been more flexible in the implementation of some measures in order to avoid potentially negative consequences of certain preventive recommendations (e.g., confinement), especially when the epidemiologic data showed that children's infection was usually mild.

According to the conceptual framework of knowledge, attitudes and practices (KAP), behaviors are influenced by knowledge about their benefits and risks, together with attitudes related to them (11). The study of these aspects in parents and other adults living with children during the pandemic can help to understand how did they live through this unique situation, and possible reasons for different preventive behaviors. It may also provide clues to evaluate the success of the information campaigns and to improve health promotion in the future in this subgroup of the population.

In the present work, we took advantage of the nationwide COSMO-SPAIN (12) and ENE-COVID (13) surveys to test the hypothesis that young and middle-aged adults living with children differ in their preventive behavior, knowledge, perception of risk, and concerns related to the COVID-19 compared to those who did not live with them. COSMO-SPAIN, the World Health Organization (WHO) Behavioral Insights survey on COVID-19 in Spain (14) is a nationwide repeated online survey designed to collect data on KAP and risk perceptions related to this disease in adult population. As for ENE-COVID (13), it is a nationwide population-based sero-epidemiological survey of SARS-CoV-2 infection in Spain with more than 50,000 participants, representative of the general population living in households in the country, which collected information on behavior related to control or reduce exposure to this virus. Both, COSMO-SPAIN and ENE-COVID had several rounds. For the present study, we will focus on data extracted from their third and fourth rounds (15, 16) respectively, which took place during November 2020.

Overall, our findings revealed that adults in general and, particularly those living with children, have a good level of knowledge on COVID-19 transmission mechanisms as well as the preventive measures to be followed. Living with children was associated to a slightly higher compliance with mask using and social distancing, with more avoidance of crowded spaces and bars, and a lower use of public transport. Also, this subgroup had specific worries related with the difficulties of having children at home (i.e., work conciliation and school closures), while they mostly considered schools as a safe place, more than those without kids at home.

The observed high level of knowledge and compliance with preventive recommendations is reassuring, since parents are the primary protectors of their children' health, being responsible for their health education together with the role of the schools (10). Indeed, the health behavior of parents may influence the children's health, by increasing or decreasing the risk of transmission of the infection both, directly by influencing children' behavior, and indirectly by reducing their own risk of infection and consequently the transmission to their children. The better the parents are informed about the preventive measures to avoid the COVID-19, the better would be their adherence to them (20). Although other factors must also be taken into account, including those related to attitudes, risk perception, self-efficacy or personality characteristics (21, 22). According to COSMO-SPAIN data, there were very small differences in the knowledge on SARS-CoV-2 transmission mechanisms and correct use of preventive measures between participants living or not with children. Only the items about timing of symptoms onset, mandatory nature of recommendations, washing hands when using a mask and efficacy of physical distance were slightly more correctly answered by people living with children (standardized differences around 2%, but with wide confidence intervals). The higher belief among this group that physical distance is an effective measure is consistent with their slightly higher compliance with the recommendation of maintaining physical distance. However, in general, the similarity in knowledge between both groups suggests that the differences observed in compliance with preventive measures would be mainly led by factors other than knowledge.

The lower risk of getting infected in education centers perceived by people living with children, compared to those living in households without children, could be related to higher knowledge of the strict control measures adopted in this environment (23), as well as to the relatively few cases identified in the outbreaks occurred in this setting since the reopening of schools in Spain in September 2020 (24–26). This supports the idea that personal experience modulates the beliefs and perceptions that the population acquires from other sources such as the media or health authorities (27, 28) and suggests that parents trusted the risk-reduction strategies adopted by health and educative authorities at that time (i.e., compulsory mask and distance at school; students' groups split into two that attended school on alternate days; entrance through different doors and at different times; or combination of onsite and online teaching).

In both studies, COSMO-SPAIN and ENE-COVID, always wearing a mask in gatherings with family or friends was much less frequent than in other settings or in general, irrespective of living in a household with or without children. This could be explained by the lower perception of risk of infection in this setting compared to public transports or crowded closed places, and to social pressure not to follow this recommendation in the familiar environment (29). Maintaining the recommended physical distance was also scarcely followed, according to COSMO-SPAIN results. As our definition of compliance implied answering that the measure was followed “always”, this low compliance may reflect the impossibility of maintaining physical distance in certain situations, e.g. in public transports or when it depends on the behavior of other people, more than a lack of commitment with compliance (29). This would be congruent with the much higher compliance found at work in the ENE-COVID study, a setting where structural and organizational measures were implemented to separate people, whenever it was feasible.

Consistently with their perception of high risk of infection in closed environments, such as bars, indoor restaurants, public transport and, to a lesser extent, during family meetings, we found that the use of masks was very frequent during displacements and during leisure time activities. Also, the higher perception of contagion risk in crowded closed spaces among those living with children was in line with the finding that they went less frequently to bars and used less the public transportation. These results are in agreement with previous studies carried out during the current COVID-19 pandemic (20) and during previous flu pandemics (30) that show that knowledge and risk perception may be key predictors of the compliance with preventive measures. However, given the cross-sectional approach of our analysis, we cannot rule out that these differences in behaviors were related to factors associated with the fact of living with children other than the different risk perception or the desire to protect kids. For instance, people living with children may have lower opportunities to socialize in bars, or more difficulties with using public transport.

A possible influence of living with children in health-related behaviors among adults has been previously reported, although results from different studies are not fully in agreement. Some authors reported healthier behaviors among people living with children, while others found no differences or opposite relations (31). Regarding preventive measures against communicable diseases, some publications reported lower COVID-19 vaccine hesitancy or higher vaccine uptake among people living with children (32, 33) as well as higher social interaction reduction among rural females living with children compared with those not living with children (34). Although small in magnitude, our findings, adjusted by potential confounding factors such as age, education, sex, living with someone older than 60 and personal history of COVID-19, would add support for a positive association between the presence of children in households and a better adherence of adults to preventive measures related to infectious diseases. A possible explanation for these differences could be that the desire of protecting children would encourage those living with them to follow more strictly the recommendations. According to the Health Belief Model, the perceived susceptibility to acquire a disease and perceived disease severity are two of the factors that influence the adoption of preventive behaviors (35, 36). Although COVID-19 has been found to be usually mild in children, the mere possibility that it could be severe may be perceived by parents as a terrible consequence and lead them to reinforce their compliance with precautions. The perception of a higher probability of getting infected, or the higher worry about restrictions such as closure of schools if epidemiological situation worsened, as were estimated from the COSMO-SPAIN data among participants living with children, could also have contributed to the slightly higher compliance observed in this group.

Adults living with children reported being worried or very worried about work and family conciliation more frequently than those not living with children. This was also reflected in their higher concern about schools closure. This last worry was probably also related to concerns about education quality. Indeed, surveys that estimate parents' concern regarding their children's education, showed more concern when their children were remote learners, perhaps partly due to the higher implication of parents in academic education it involved (37, 38), a task for which not all of them felt well prepared. Lack of the necessary technological resources for the online education could also explain this finding. Considering the importance of this issue (more than 60% of COSMO-SPAIN participants were worried or very worried about it), both educators and policymakers face an important challenge to find effective strategies to improve the child learning experience during this singular situation (39, 40) and to avoid increasing inequity. Achieving these goals would have a positive impact, not only in children, but also in their parents, by alleviating the increased stress parents may suffer from this situation, especially if they have jobs with higher conciliation difficulties and if no changes in workplace policies have been made to protect workers with dependent children (41).

Some aspects of this study can be highlighted as its main strengths. Firstly, we used data from two nationwide studies with information on behavior and about KAP, which have not been extensively studied in such big samples. The study designs made it possible to analyze differences between two population groups (based on the presence or absence of children in the household) regarding the compliance with preventive measures facing SARS-CoV-2 infection, and to identify that there were some specific concerns related to the pandemic in each of these groups. Secondly, all data were collected during the same period and therefore explore the same epidemiological context and containment measures. This allowed us to compare the information and to do a parallel analysis. Both surveys complement each other with study-specific information derived from their different focus, i.e., a biomedical and behavioral focus in the ENE-COVID, and a psychosocial focus in COSMO-SPAIN. In both studies the participation rate was high. Also, the sampling design of the ENE-COVID survey, together with statistical analyses that took into account sampling weights and differential non-response, make its results representative of the Spanish non-institutionalized population.

Yet, our study has also several limitations. Comparison between both studies is hampered by their different sample selection and data collection methods (i.e., random selection and face-to-face or telephone interviews in ENE-COVID, panel data and online survey in COSMO-SPAIN). The higher proportion of participants in the youngest age group and with university education in the COSMO-SPAIN compared to the ENE-COVID study may be due to these differences. This also may imply a variation in the validity of the answers collected, and different selection biases may appear: in the case of online self-administered questionnaires such as the COSMO-SPAIN study, they require internet literacy. In the case of interview-administered questionnaires, the presence of the interviewer may help to reduce the uncertainty that respondents may experience with some items, thereby increasing the validity of the results (42), but also may increase the risk of social desirability bias. In this sense, the fact that information on behaviors was self-reported, may have led to some overestimation of the degree of compliance. Also, the differences observed between groups could be overestimated if people living with children were more prone to the social desirability bias. Although we are not aware of any evidence on a differential tendency to this bias depending on the presence of children in the household, parents could be more susceptible to it, given that they are supposed to act as a model for their children. On the other hand, in ENE-COVID, a large number of professionals were involved in data collection, which may have introduced variability in the process, in spite of the shared training platform established and the monitoring of the data collection. Lastly, although we carefully selected the questions that were similar enough in the respective questionnaires to be compared between studies, their wording and time frame were not identical and, therefore, they could have some different nuances that limits their comparability.

Our findings reinforce the need for providing support to parents and children to adapt to children distance learning and to coordinate work and family life. In order to improve COVID-19 related knowledge, a better communication about timing of symptoms' onset once infection has been acquired would be useful, since this was one of the worst answered items both in participants with and without children. Reinforcing the importance of wearing a mask also in gatherings with family and friends, again in both groups, could contribute to improve control of SARS-CoV-2 transmission.

The juxtaposition of the results of the COSMO-SPAIN and the ENE-COVID surveys showed that during the second wave of the pandemic in Spain, young and middle-aged adults living with children adopted some social distancing measures to prevent the transmission of SARS-CoV-2 slightly more frequently than those living without children. Putting the results of these two studies together highlighted the consistency of the information provided by them. It also showed that different research approaches can be able to provide complementary answers to a common public health issue and make the understanding of the problem more complete, which could aid in the formulation of more precise public health recommendations.

The datasets presented in this article are not readily available because of privacy issues, but COSMO-SPAIN data is available from the authors upon reasonable request, and ENE-COVID data will be available under approval by a Scientific Board that will evaluate the petitions and guarantee the safeguard of participants' rights, under the limits imposed by the Ethics Committee. Requests to access the datasets should be directed to cosmo-spain@isciii.es and to follow the procedure at the study webpage https://portalcne.isciii.es/enecovid19.

The studies involving human participants were reviewed and approved by the Research Ethics Committee of the Instituto de Salud Carlos III. Written informed consent to participate in this study was provided by the participants or the participants' legal guardian/next of kin.

Spanish Ministry of Health: Pilar Aparicio Azcárraga; Faustino Blanco; Rodrigo Gutiérrez Fernández; Mariano Martín; Saturnino Mezcua Navarro; Marta Molina; Juan F. Muñoz-Montalvo; Matías Salinero Hernández; Jose L. Sanmartín. Institute of Health Carlos III: Manuel Cuenca-Estrella; José León Paniagua; Raquel Yotti; National Center of Epidemiology: Nerea Fernández de Larrea Baz; Pablo Fernández-Navarro; Roberto Pastor-Barriuso; Beatriz Pérez-Gómez; Marina Pollán; National Center of Microbiology: Ana Avellón; Giovanni Fedele; Aurora Fernández-García; Jesús Oteo Iglesias; María Teresa Pérez Olmeda; National School of Public Health: Israel Cruz; Maria Elena Fernández Martínez; Francisco D. Rodríguez-Cabrera. Harvard T.H. Chan School of Public Health: Miguel A. Hernán. Spanish Regional Health Services: Andalucía: José M. Navarro Marí; Susana Padrones Fernández; Begoña Palop Borrás; Ana Belén Pérez Jiménez; Manuel Rodríguez-Iglesias; José Manuel Rumbao Aguirre. Aragón: Ana María Calvo Gascón; María Luz Lou Alcaine. Asturias: Ignacio Donate Suárez; Mercedes Rodríguez Pérez; Oscar Suárez Álvarez. Baleares: Lluis Carbo Saladrigas; Margarita Cases Sanchís; Adoración Hurtado Fernández; Antonio Oliver; Carlos Javier Villafáfila Gomila. Canarias: José María Barrasa Fernández; Elías Castro Feliciano; María Noemí González Quintana; María Araceli Hernández Betancor; Melisa Hernández Febles; Leopoldo Martín Martín. Cantabria: Inés De Benito Población; Luis-Mariano López López; Teresa Ugarte Miota. Castilla-La Mancha: María Sagrario Celada Pérez; María Natalia Vallés Fernández. Castilla y León: Marta Domínguez-Gil González; Isabel Fernández-Natal; Tomás Maté Enríquez; Gregoria Megías Lobón; Juan Luis Muñoz Bellido; Miguel Villa Arranz. Cataluña: Pilar Ciruela; Maria Doladé Botías; M. Angeles Marcos Maeso; Ariadna Mas i Casals; Dúnia Pérez del Campo. Comunidad Valenciana: Antonio Félix de Castro; Ramón Limón Ramírez. Extremadura: Maria Francisca Elías Retamosa; Manuela Rubio González. Galicia: Antonio Aguilera; María Sinda Blanco Lobeiras; German Bou; Alberto Fuentes Losada. La Rioja: Yolanda Caro; Noemí Marauri; Luis Miguel Soria Blanco. Madrid: Roberto Alonso Fernández; Isabel del Cura González; Montserrat Hernández Pascual; Paloma Merino-Amador. Murcia: Natalia Cabrera Castro; Cristóbal Ramírez Almagro; Manuel Segovia Hernández; Aurora Tomás Lizcano. Navarra: Nieves Ascunce Elizaga; María Ederra Sanz; Carmen Ezpeleta Baquedano. País Vasco: Ana Bustinduy Bascaran; Luis Elorduy Otazua; Susana Iglesias Tamayo. Ceuta: Rebeca Benarroch Benarroch; Jesús Lopera Flores. Melilla: Antonia Vázquez de la Villa.

IJ, MF, BP-G, and RP-B were responsible for the conceptualization and design of this study. IJ and NF performed the statistical analysis, developed the tables and figures design, and drafted all manuscript versions. IJ, CR-B, RP-B, MF, MP-S, and BP-G contributed to interpretation of data. All authors have contributed to reviewing and editing the last version of the manuscript.