Factors associated with change in adherence to COVID-19 personal protection measures in the Metropolitan Region, Chile.

Personal protective measures such use of face masks, hand washing and physical distancing have proven to be effective in controlling the spread of the Covid-19 pandemic. However, adherence to these measures may have been relaxed over time. The objective of this work is to assess the change in adherence to these measures and to find factors that explain the change For this purpose, we conducted a survey in the Metropolitan Region of Chile in which we asked the adherence to these measures in August-September 2021 and retrospectively for 2020. With the answers obtained we fit a logistic regression model in which the response variable is the relaxation of each of the self-care preventive actions. The explanatory variables used are socio-demographic characteristics such as the age, sex, income, and vaccination status of the respondents. The results obtained show that there has been a significant decrease in adherence to the three personal protection measures in the Metropolitan Region of Chile. In addition, it was observed that younger people are more likely to relax these measures. The results show the importance of generating new incentives for maintaining adherence to personal protection measures.

1. Introduction

Since 2020 the world has been affected by a pandemic caused by the SARS-CoV-2 virus that causes the Covid-19 disease. One of the first defenses against the transmission of this virus are the self-care preventive actions, such as the use of facemasks, hand washing, and keeping a physical distance, all recommended by the World Health Organization (WHO) and other health public institutions [1, 2]. These measures have proven to be very efficient in controlling the advance of this virus [3-5]. However, due to pandemic fatigue and the advent of vaccines, some evidence suggests that adherence to these measures may have relaxed during the course of the pandemic [6-8]. Adherence to these recommendations continues to be a challenge due to local inequalities, cultural differences and associated changes in people’s behavior [9-14].

This study assesses adherence to self-care preventive actions in the Metropolitan Region of Chile. For this purpose, a survey was performed in which we asked for the adherence to the use of facemasks, hand washing, and keeping a physical distance in August-September 2021 and retrospectively during 2020.

This survey was implemented in a period of transition between two Covid-19 waves, according to the wave definition given by [15]. The weekly moving average of the confirmed cases of Covid-19 in the Metropolitan Region of Chile at that time was 4 cases per 100.000 inhabitants [16]. According to the guidelines of the Health Ministry of Chile, the Metropolitan Region had opened the lockdowns due to Covid-19.

Regarding vaccines, Chile has had a successful campaign [17], reaching more than 80% of the Chilean population fully vaccinated and more than 60% with a booster dose by December 2021. However, these vaccination levels have not been distributed homogeneously in the country. Particularly in the Metropolitan Region of Chile, a high level of heterogeneity between its municipalities has been observed both in the vaccination progress and in the number of people who have been infected.

Despite the progress of the vaccination campaign in Chile, greater protection can be achieved if the vaccine is complemented with self-care preventive actions [18]. Moreover, it has become very relevant to reinforce our protection due to the arrival of more contagious variants of SARS-CoV-2 such as delta or omicron.

In this context, it is interesting to assess whether the self-care preventive actions have decreased their adherence in Chile. Consequently, the main objective of this article is to assess the change in adherence to the COVID-19 personal protective measures in the Metropolitan Region and to identify factors associated that could explain the relaxation of these measures.

2. Methods and materials

Study design and setting

This is a cross-sectional study, although with a longitudinal focus, since adherence to preventive measures was consulted at two different points in time. The period covered is 2020 and 2021 (August-September).The study was conducted in the Metropolitan Region of Chile, considering responses from 48 municipalities of the 6 provinces of this region.

This region was selected because it is the main region of Chile, where more than 40% of the total population of the country lives. In addition, in the first pandemic wave this region reached the highest mortality rate of the country.

In order to incorporate a spatial component to the analysis, the nearest health service according to the reported residence of the participant was considered. The Chilean health system uses a geographic administrative division to organize health services for the population. Thus, the Metropolitan Region has six major health service areas: north, west, center, east, south and south-east.

Sampling method and sample size

A non-probabilistic purposive sampling was applied throughout the Metropolitan Region, considering responses from all provinces of the region. The sample size included 635 responses, 66 of which were validated by phone call, verifying the authenticity of the information provided. The sampling size was intentionally completed to meet quotas for geographic, socioeconomic and sex representation

Data collection

The information was obtained through an online questionnaire, disseminated in the social networks between August 6 and September 8, 2021.

The survey inquired about the frequency of the application of three COVID-19 personal protection measures: use of facemasks, hand washing, and physical distancing. Participants were asked about the adherence at the current time (August-September 2021) and retrospectively for 2020. The frequency of implementation of preventive measures included: almost never, sometimes, most of the time, and always. In addition, the participants were asked about their age, sex, level of household income, area of residence and whether they had been vaccinated, they intended to do it, or did not want to get the vaccine.

To record the change between the years 2020 and 2021, a variable was created with three categories to identify individuals that increased, maintained, or decreased adherence to each of the COVID-19 preventive measures. The Wilcoxon signed-rank test for paired data [19] was used to assess whether the change in adherence in each measure was statistically significant. If the null hypothesis of this test is rejected then the reduction of adherence is significant.

Data analysis

In order to explain the change in adherence to the COVID-19 preventive measures, we performed a logistic regression model for each self-care measure. For this purpose, the change in the adherence was dichotomized for each self-care measure taking the value 1 if a person increases or maintains adherence and as 0 if a person decreases its adherence. In order to assess the sensitivity of this categorization, we compared the results obtained with an ordinal logistic regression where the response variable was defined in the following order (increases adherence, maintains adherence, and decreases adherence).

For each logistic regression, a set of socio-demographic characteristics of the participants of the survey was included. The explanatory variables included the per capita household income (divided into three continuous groups; High socioeconomic group with a monthly income above 1,500,000 Chilean pesos, Medium with income between 1,500,000 and 500,000 Chilean pesos, and Low with income below 500,000 Chilean pesos), sex, age, vaccination (asked about having received at least one dose) and the nearest health service according to the reported residence of the participant.

The effect of the explanatory variables are presented in terms of Odds Ratio, and represents the probability of decreasing adherence versus the probability of maintaining or increasing adherence, where values close to 1 express equal probability or absence of effect, values above 1 indicate a positive effect, and coefficients below 1, a negative effect. Likewise, the confidence interval (CI) of each estimate is included with 95% statistical confidence (p<0.05).

Ethical considerations

The survey had the informed consent of the participants. Participation was completely voluntary, with no risks or benefits for the respondents. The information collected was handled anonymously and confidentially. The research was approved by the Ethical Review Committee of the Universidad de Santiago, Chile.

3. Results

The sample obtained in the survey is composed as follows: 56.8% reported themselves as women and 41.5% as men, while 1.7% reported themselves as neither of the above. The age range was between 18 and 74 years. Regarding monthly household income, 33% reported earning less than 500,000 Chilean pesos, 44% reported earning between 500,000 and 1,500,000 Chilean pesos, and 23% reported earning more than 1,500,000 Chilean pesos. When asked about vaccination status, 95.8% reported having at least one dose, while 3.8% reported not being vaccinated (either because they do not want to, because they have not yet decided to do so, or because they are waiting to do so) and 0.5% marked don’t know/no answer. In relation to the nearest metropolitan health service reported, 16.7% corresponded to the East, 8.5% to the North, 20.5% to the West, 19.2% to the Center, 13.4% to the South and 21.7% to the South-East.

In relation to the use of facemasks, Fig 1 shows that 4.4% of the sample increased their adherence between the years 2020 and 2021, 85.8% maintained it, and 9.8% decreased it. With respect to hand washing, 5.8% increased their adherence, 73.1% maintained it, and 21.1% decreased it. Finally, regarding physical distancing, 3.5% increased their adherence to this behavior, 55.1% maintained it and 41.4% decreased it. In other words, physical distancing is the measure with the highest decrease in adherence in the year 2021.

Fig 1

Change (%) in the frequency of COVID-19 personal protection measures between 2020 and 2021.

The p-values obtained from the Wilcoxon signed rank test for the three preventive measures were less than 0.001. Therefore, the reduction in adherence observed in the descriptive analysis is statistically significant.

Table 1 shows the logistic regression models fitted to explain the relaxation of the three COVID-19 personal protection measures. As can be seen, for the use of facemasks and hand washing, the household income, sex, vaccination, and the metropolitan health service had no significant effect. On the other hand, it was observed that the higher the age, the chances of decreasing the frequency of facemask use and handwashing decreased statistically significantly.

Table 1

Logistic regression models for the change in the COVID-19 personal protection measures (facemask use; hand washing; distancing) between 2020 and august-september 2021.

	Facemask use		Hand washing		Distancing
Predictors	Odds Ratio	CI	Odds Ratio	CI	Odds Ratio	CI
(Intercept)	0.199 *	0.052 – 0.712	1.250	0.488 – 3.206	2.860 *	1.281 – 6.451
Household income	0.997	0.664 – 1.492	1.152	0.857 – 1.551	1.032	0.806 – 1.323
Sex (Ref = Woman): Man	1.449	0.833 – 2.513	0.726	0.473 – 1.104	0.531 ***	0.374 – 0.751
Age	0.973 *	0.948 – 0.997	0.960***	0.941 – 0.979	0.970 ***	0.955 – 0.985
Vaccine (Ref = Vaccinated):Unvaccinated	2.005	0.562 – 5.634	0.899	0.254 – 2.495	0.322 *	0.091 – 0.892
MHS (Ref = East): North	1.259	0.393 – 3.787	0.573	0.237 – 1.302	1.059	0.520 – 2.150
MHS (Ref = East):West	1.378	0.556 – 3.593	0.576	0.290 – 1.135	0.721	0.400 – 1.297
MHS (Ref = East): Central	1.044	0.413 – 2.719	0.540	0.277 – 1.043	0.806	0.459 – 1.415
MHS (Ref = East): South	0.975	0.339 – 2.760	0.542	0.256 – 1.118	0.798	0.426 – 1.487
MHS (Ref = East):South-East	0.808	0.304 – 2.166	0.736	0.393 – 1.378	0.835	0.480 – 1.451
Observations	622		622		619
R2 Tjur	0.015		0.043		0.071
Deviance	389.753		612.711		794.436
AIC	409.753		632.711		814.436
log-Likelihood	-194.876		-306.355		-397.218

Note:

* p<0.05

** p<0.01

*** p<0.001

MHS: Metropolitan Health Service.

This age effect is also observed for physical distancing. However, we also found significant effects of sex and vaccination status in the relaxation of this measure. According to the odds ratio estimated, men have approximately a half probability of relaxing physical distancing than women. In addition, respondents that are unvaccinated have a lower probability to relax this measure than the respondents that have at least one dose of the vaccine. Finally, the income and the nearest metropolitan health service show no significant effects.

The results presented above are consistent with those obtained in the ordinal logistic regression used to evaluate its sensitivity. For instance, in the ordinal logistic regression for both hand washing and physical distancing, it was found that younger people are more likely to relax adherence to preventive self-care measures. In addition, in the ordinal logistic regression for physical distancing we also found significant effects of the sex and the vaccination status. The only difference found in the sensitivity analysis was observed in the face mask use model, since in this model no significant variables were obtained for the ordinal logistic regression.

A more intuitive way to show these results comes from the estimated marginal probabilities for each model. We focus on calculating these probabilities for different ages since the effect of this variable was significant in all models. In Fig 2 we show these probabilities for the models of facemask use and hand washing. Note that in both cases as age increases, the probability of relaxing these measures decreases. More specifically, the probability of relaxing the mask use estimated by the logistic regression decreases from 0.13 in 18-year-olds to 0.04 in 74-year-olds, while for hand washing this probability decreases from 0.31 to 0.05.

Fig 2

Probabilities estimated by logistic regression for age in the mask use (left) and hand washing (right) models with confidence intervals of 95%. The probabilities shown in the figure were estimated by a logistic regression fitted with only the significant variables at level 5%.

For the physical distancing model, we calculated the marginal probabilities using age and sex since they showed a significant effect in the logistic regressions (Table 1). As presented in Fig 3, the predicted probabilities of relaxing physical distancing are consistently higher for women than for men. This relaxation can be understood by the fact that in the baseline (year 2020) women had a higher adherence to the physical distance than men, but by the year 2021 this adherence tends to equalize between both sexes. Moreover, for people between 20 and 45 years of age, the differences in the predicted probabilities for women and men are statistically significant. For women, the probability of relaxing physical distancing decreases from 0.6 at age 18 to 0.22 at age 74. On the other hand, the probability of relaxing physical distance decreases from 0.43 for 18-year-old men to 0.13 for 74-year-old men.

Fig 3

Probabilities estimated by logistic regression for age and sex in the distancing model and with confidence intervals of 95%.

The probabilities shown in the figure were estimated by a logistic regression fitted with only the significant variables at level 5%.

4. Discussion

This study aims to determine the relaxation of adherence to three preventive self-care measures for Covid-19 in the Metropolitan Region, Chile in August-September 2021 with respect to 2020, as well as the factors that explain this relaxation. The results obtained show that the three measures studied, use of facemasks, hand washing, and keeping a physical distance had lower adherence in 2021 than in 2020.

Regarding to the objective of assessing the factors associated with changes in adherence to personal protective measures, this study shows that the age of the respondents has a significant effect on this relaxation for the three measures studied so that young people are more likely to relax these measures, while older people were more likely to maintain adherence to preventive measures over time. This age effect has also been reported in other studies [6, 7, 20–24]. This effect may be explained by differences in the perception of the severity of the virus. Some studies point out that older people experience greater nervousness, perceive greater severity and take fewer risks in the face of the virus than younger people [25-27], although contradictory results have also been reported [28, 29].

Furthermore, for the physical distancing model, we also reported a statistically significant effect of the sex of the respondents. Particularly, a greater relaxation of physical distance was found in women. This is partly explained by the fact that women had a higher baseline adherence than men. Some studies have also reported the higher adherence to physical distancing of women in the pandemic first year [24, 30, 31]. However, the higher initial adherence of women led to a more pronounced relaxation until reaching a similar adherence to this measure in 2021 than men. Finally, people who have not been vaccinated are less likely to relax the physical distance. Household income and the nearest metropolitan health service did not show a significant effect on the response variable.

Some limitations of this study are the bounded information from the survey; we preferred to create an instrument with few questions to ensure a good response rate. A panel study could help monitoring and assessing these effects in the future. In addition, the proportion of vaccinated people in the sample was higher than that observed in the population. A challenge for further extensions of this work is to achieve more responses from unvaccinated persons, particularly since this showed to be a relevant factor explaining protective behaviors. In addition, as the survey was conducted in a period between two waves of covid, the participants’ answers of this survey could be affected by a less risk perception of the people.

Finally, the application of an online survey introduces certain biases. Although it is estimated that Internet coverage has grown substantially in recent years, only 67.48% of the country’s households have a fixed Internet connection [32]. Although this average percentage is higher in the Metropolitan Region, the Internet coverage gap between vulnerable households and the most advantaged households is still very wide [33]. Consequently, there is a possibility that the results only represent only those who have access to the Internet. This issue was addressed by incorporating individuals from households with different socioeconomic incomes to meet quotas of all socioeconomic groups.

5. Conclusions

As long as there is no global control of the Covid-19 pandemic, the relaxation of these measures could increase the risk of infection due to the emergence of new variants of the virus, as has been observed in Chile and other countries during 2022.

The results of this study suggest the need to generate new incentives for the use of personal protection measures, considering their effectiveness in preventing Covid-19 infection. Efforts could concentrate on the younger population, where adherence to Covid-19 protective measures has declined more sharply. An adequate risk communication must be performed in order to explain the importance of maintaining these preventive measures.

In addition, some incentives that can be promoted include better access to quality face masks and hand hygiene items and ensuring that capacity limits in enclosed places or on public transport are respected.

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7 Mar 2022

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Reviewer #1: The work by Varas et al. evaluates the factors associated with relaxation to personal protection measures in Chile. The work was well contextualized and with sufficient methods to achieve the proposed objectives. However, there are issues that need to be addressed before the paper can be considered for publication.

1. A thorough review of the English is required. Some sentences need to be rephrased such as “In this context, it is interesting to assess whether the self-care preventive actions have decreased their adherence in Chile.” This and some other sentences don’t make sense.

2. Reevaluate the title – “in the metropolitan area region, Chile”. The name of the city is missing.

3. Citation to Mackay (2020) - please elaborate on this as it does not seem to make sense. The page cannot be found.

4. Material and methods: please include the questionnaire in the suppl material for those interested in the research protocol.

5. Since the research was performed with human subjects, it is necessary to include information on ethics approval by an ethics committee.

6. Figure legend is lost in the text. There seems to be a problem with the text format overall.

7. Figure 2 only shows age but above it, it says age and sex. It is not clear what the probability means.

8. Figure 3 – what is predictive margin? All figure legends should be self-explanatory.

9. Text brings some discrepancies that need to be clarified. In some parts authors state that older people have lower adherence to preventive self-care measures, but in other parts, including the summary, it says that young people are more likely to relax these measures. The same is true for comparisons between men and women. In several parts of the text, it is said that women are more likely to relax physical distancing, but in the discussion authors state that “This result has also been found in other studies, showing that women are more likely to adhere to physical distancing than men”.

I also encourage authors to take a look at a similar research by Finger et al. 2021 -

https://doi.org/10.1016/j.tifs.2021.03.016

10. In the final paragraph of the Results (“For the physical distancing model, we calculated…”), the same sentence is written twice: “As presented in Figure 3, the predicted probabilities of relaxing physical distancing are consistently higher for women than for men. The likelihood of relaxing physical distance is consistently higher for women than for men.”

11. I missed a deeper discussion, comparing the results with other works, especially considering that this subject has been extensively researched.

Reviewer #2: General comments

This a very well researched study on an important topic: the prevention and control of COVID-19 in Chile. Despite the availability of potent vaccines and of late, treatment options, the use of public health preventive measures remain very critical for flattening the curve. In general, the manuscript is succinct and very well written. Nevertheless, I believe that there is some room for the authors to further improve the quality of the document which if accepted for publication could boost readership and article metrics.

I have observed an important methodological flaw of the study which would require further elaboration. Because it was conducted online, there is the possibility that the findings may only represent adherence of people who use the internet, who are more likely to be better educated and well informed. This raises a few questions which require further explanation in the manuscript. In view of this limitation, are the findings generalizable to the general population of Metropolitan Region of Chile? Could this have caused a bias in the findings and if yes, how did the authors minimized such bias? I believe that there are opportunities to correct this limitation in the revised version of the document. Are there available data on the adherence of non-internet/social media users in Chile or similar settings? Are there other studies that looked at adherence in less educated and low socioeconomic class to which your findings could be compared? Below are a few specific comments on how to improve the manuscript:

Abstract

This section is well written and could be understood as a stand-alone document. I would suggest inclusion of a sentence on your conclusion and recommendation at the end of the section.

Introduction

While this section has most of the required elements, 2-3 sentences on the COVID-19 situation and trends in the study areas should be included in the first paragraph of the section to set the tone for the study and contextualize your findings.

Methods

While this section is well written, further information on the study methods would improve the understanding and reproducibility of the study design. Furthermore, to demonstrate the validity of your findings, it is important to briefly describe how your sample size was calculated (detailed formulas and description could be included as an annex). I would suggest reorganization of this section into the following sub-sections:

�  Study design and setting: what type of study is this? What period was covered? The social, demographic, geographic and public health context of the study area as they relate to the subject matter? A brief introduction of the Metropolitan Health Services would also be useful to better contextualize your findings

�  Sampling method and sample size: how was the sample size calculated? What sampling method did you use? What was rationale for selecting the Metropolitan Region? Was it for convenience?

�  Data collection: description of the data collection tool (questionnaire); how many sections does it have, how many questions? This is already well presented in the current “data” sub-section.

�  Data analysis: This is already well presented in the current “logistic regression” sub-section.

Results

The study findings are well presented

Discussion

The discussion is well written. However, more in-depth description and rationalization of your findings would be helpful. While the authors have compared their findings to those of other studies, it would be useful to describe/discuss the factors that could have been responsible for these findings/trends in this setting. I would therefore suggest that you reorganize this section as follow for better flow and clarity:

o Paragraph 1: a very brief statement of the main objective and key findings of this study.

o Paragraphs 2-4: exhaustive discussion and rationalization of the key findings of the study. Which factors could have been responsible for the observed trends i.e. 1) the significant relaxation of the preventive measures, 2) the effect of age on the adherence to the measures, 3) the effect of gender (sex) on physical distancing and 4) the effect of vaccination? What were the findings of other similar studies? Are they comparable to your findings?

o Paragraph 5: study limitations. The authors should include the skewness of the study findings to only internet/social media as a limitation and what was done to address this or whether their findings are generalizable.

Conclusion

A conclusion section should be introduced to further elaborate on the “new incentives” which was proposed in the last paragraph of the discussion section.

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Reviewer #1: No

Reviewer #2: Yes: Olushayo Oluseun Olu

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25 Mar 2022

We would like to thank the comments from the Editor and the reviewers, which have helped to substantially improve the manuscript. In what follows, we respond to each issue separately.

Reviewer #1: The work by Varas et al. evaluates the factors associated with relaxation to personal protection measures in Chile. The work was well contextualized and with sufficient methods to achieve the proposed objectives. However, there are issues that need to be addressed before the paper can be considered for publication.

1. A thorough review of the English is required. Some sentences need to be rephrased such as “In this context, it is interesting to assess whether the self-care preventive actions have decreased their adherence in Chile.” This and some other sentences don’t make sense.

We have revised the writing of the article and made some changes, which are highlighted in the document "Revised manuscript with track changes".

2. Reevaluate the title – “in the metropolitan area region, Chile”. The name of the city is missing.

The country is administratively divided into regions. The study was conducted in the Metropolitan Region of Chile. This region is composed of 52 municipalities belonging to 6 provinces, including the city of Santiago (national capital). In the survey we obtained responses from all the provinces, so we believe it would not be correct to add in the title the name of only one city. The reasons for studying this region were outlined in the Study design and setting paragraph of the Methods and Materials section.

3. Citation to Mackay (2020) - please elaborate on this as it does not seem to make sense. The page cannot be found.

The link to Mackay (2020) has been corrected. In addition, the sentence that included this citation was rewritten.

4. Material and methods: please include the questionnaire in the supply material for those interested in the research protocol.

The questionnaire was included in the new section “supplementary material”

5. Since the research was performed with human subjects, it is necessary to include information on ethics approval by an ethics committee.

We include in the section “Methods and materials” a subsection called “Ethical consideration”. Here we include the approval of this project by the Ethical Review Committee of the Universidad de Santiago, Chile.

6. Figure legend is lost in the text. There seems to be a problem with the text format overall.

The caption of figures 2 and 3 was rewritten in order to make them easier to understand.

7. Figure 2 only shows age but above it, it says age and sex. It is not clear what the probability means.

8. Figure 3 – what is predictive margin? All figure legends should be self-explanatory.

Throughout the manuscript we have replaced the term "predict margins" with "predict probabilities". Figure titles were rewritten.

9. Text brings some discrepancies that need to be clarified. In some parts authors state that older people have lower adherence to preventive self-care measures, but in other parts, including the summary, it says that young people are more likely to relax these measures. The same is true for comparisons between men and women. In several parts of the text, it is said that women are more likely to relax physical distancing, but in the discussion authors state that “This result has also been found in other studies, showing that women are more likely to adhere to physical distancing than men”.

The sentence “older people have lower adherence to preventive self-care measures” have been rewritten to “ younger people are more likely to relax adherence to preventive self-care measures”. However, it is important to note that the concepts of adherence and relaxation are not equivalent. For example, women adhere more to preventive self-care measures in 2020, but they also relaxed more and achieved similar adherence to men in 2021. We add a sentence in the same paragraph to explain this.

I also encourage authors to take a look at a similar research by Finger et al. 2021 - https://doi.org/10.1016/j.tifs.2021.03.016

This text was also incorporated to enrich the introduction of the study.

10. In the final paragraph of the Results (“For the physical distancing model, we calculated…”), the same sentence is written twice: “As presented in Figure 3, the predicted probabilities of relaxing physical distancing are consistently higher for women than for men. The likelihood of relaxing physical distance is consistently higher for women than for men.”

The second sentence of this paragraph was removed from the manuscript.

11. I missed a deeper discussion, comparing the results with other works, especially considering that this subject has been extensively researched.

We improved the discussion section. For this purpose, we added further rationalization of our findings. In addition, the discussion was enriched with a greater number of references.

Reviewer #2: General comments

This a very well researched study on an important topic: the prevention and control of COVID-19 in Chile. Despite the availability of potent vaccines and of late, treatment options, the use of public health preventive measures remain very critical for flattening the curve. In general, the manuscript is succinct and very well written. Nevertheless, I believe that there is some room for the authors to further improve the quality of the document which if accepted for publication could boost readership and article metrics.

I have observed an important methodological flaw of the study which would require further elaboration. Because it was conducted online, there is the possibility that the findings may only represent adherence of people who use the internet, who are more likely to be better educated and well informed. This raises a few questions which require further explanation in the manuscript. In view of this limitation, are the findings generalizable to the general population of Metropolitan Region of Chile? Could this have caused a bias in the findings and if yes, how did the authors minimized such bias? I believe that there are opportunities to correct this limitation in the revised version of the document. Are there available data on the adherence of non-internet/social media users in Chile or similar settings? Are there other studies that looked at adherence in less educated and low socioeconomic class to which your findings could be compared? Below are a few specific comments on how to improve the manuscript:

Abstract

This section is well written and could be understood as a stand-alone document. I would suggest inclusion of a sentence on your conclusion and recommendation at the end of the section.

We included a sentence in the abstract about our conclusions and recommendations.

Introduction

While this section has most of the required elements, 2-3 sentences on the COVID-19 situation and trends in the study areas should be included in the first paragraph of the section to set the tone for the study and contextualize your findings.

In the Introduction section, we included a paragraph mentioning the context of the virus circulation and confinement conditions in the Metropolitan Region at the moment the survey was carried out.

Methods

While this section is well written, further information on the study methods would improve the understanding and reproducibility of the study design. Furthermore, to demonstrate the validity of your findings, it is important to briefly describe how your sample size was calculated (detailed formulas and description could be included as an annex). I would suggest reorganization of this section into the following sub-sections:

Study design and setting: what type of study is this? What period was covered? The social, demographic, geographic and public health context of the study area as they relate to the subject matter? A brief introduction of the Metropolitan Health Services would also be useful to better contextualize your findings

Sampling method and sample size: how was the sample size calculated? What sampling method did you use? What was rationale for selecting the Metropolitan Region? Was it for convenience?

Data collection: description of the data collection tool (questionnaire); how many sections does it have, how many questions? This is already well presented in the current “data” sub-section.

Data analysis: This is already well presented in the current “logistic regression” sub-section.

The methods section has been restructured according to these recommendations. Consequently, we add four sub-sections: Study design and setting, sampling method and sample size, data collection and data analysis.

Results

The study findings are well presented

Discussion

The discussion is well written. However, more in-depth description and rationalization of your findings would be helpful. While the authors have compared their findings to those of other studies, it would be useful to describe/discuss the factors that could have been responsible for these findings/trends in this setting. I would therefore suggest that you reorganize this section as follow for better flow and clarity:

o Paragraph 1: a very brief statement of the main objective and key findings of this study.

o Paragraphs 2-4: exhaustive discussion and rationalization of the key findings of the study. Which factors could have been responsible for the observed trends i.e. 1) the significant relaxation of the preventive measures, 2) the effect of age on the adherence to the measures, 3) the effect of gender (sex) on physical distancing and 4) the effect of vaccination? What were the findings of other similar studies? Are they comparable to your findings?

o Paragraph 5: study limitations. The authors should include the skewness of the study findings to only internet/social media as a limitation and what was done to address this or whether their findings are generalizable.

According to this comment, the discussion section was reorganized as follows:

Paragraph 1: Main objective and the key finding of this study.

Paragraph 2: The effect of age on the adherence to the three self-care preventive measures.

Paragraph 3: The effect of sex and vaccination on relaxation the adherence of physical distance.

Paragraph 4: Limitations of this study.

Paragraph 5: Limitation of the survey due to the collection of responses through social networks.

In addition, we add a more detailed discussion of each of our findings, with further references to other similar studies.

Conclusion

A conclusion section should be introduced to further elaborate on the “new incentives” which was proposed in the last paragraph of the discussion section.

Section 5 "Conclusions" has been included in the manuscript. In this section, we include some examples of incentives that can be promoted in order to maintain the adherence to these measures.

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

8 Apr 2022

Factors associated with change in adherence to COVID-19 personal protection measures in the Metropolitan Region, Chile.

PONE-D-22-04553R1

Dear Dr. Elorrieta,

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Reviewer #2: Yes: Olushayo Olu

4 May 2022

PONE-D-22-04553R1

Factors associated with change in adherence to COVID-19 personal protection measures in the Metropolitan Region, Chile.

Dear Dr. Elorrieta:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

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