The primary purpose of this study is to assess the feasibility and acceptability of a coping and resilience intervention for adolescents in school settings named CERIA, in the post-coronavirus disease 2019 or COVID-19 era. Whereas the secondary purpose of this study is to assess the effect of the intervention among adolescents on several outcomes, including posttraumatic stress disorder (PTSD) symptoms, defensive coping, courageous coping, social support, resilience, and health-related quality of life (HRQOL), in the post-COVID-19 era, at baseline or pre-test (one week before), right after/immediate effect or post-test (one week after), and one-month follow-up or short-term effect (one month after intervention).

The research questions in this study include the following:

• Is CERIA feasible for adolescents in the post-COVID-19 era?
• Is CERIA acceptable for adolescents in the post-COVID-19 era?
• What is the effect of CERIA on PTSD symptoms, defensive coping, courageous coping, social support, resilience, and HRQOL in adolescents in the experimental group compared to those in the control group in the post-COVID-19 era?
• Are there any differences in the mean scores of PTSD symptoms, defensive coping, courageous coping, social support, resilience, and HRQOL between the experimental and control groups at:
• one week before,
• one week after, and
• one month after CERIA?

Participants in the experimental group will be given six-weekly 45-60 minutes CERIA sessions, whereas participants in the control groups will be treated as active control. Researchers will compare the experimental and control groups to see the effect of the intervention (CERIA) to decrease the adolescents' PTSD symptoms and defensive coping and increase courageous coping, social support, resilience, and HRQOL at three different time points: one week before intervention, one week after intervention, and one month after the intervention.

Content Validity for the Intervention (An Expert Panel)

The content validity for the CERIA is aimed to validate the appropriateness of CERIA by an expert panel. Panel members will be selected based on their educational expertise and experiences related to the study. The experts who will be invited to participate in the panel have to meet the following criteria: 1) have more than five years of clinical or research experience in psychoeducation, adolescents, and/or related field, 2) be willing to participate in the content validity study, and 3) be able to effectively communicate in either English or Indonesian language. Since this study will be conducted in the school setting, panel members can include university/ faculty members who have experience with the study topic, school counselors (teachers who are responsible for counseling programs in the school), assistant principal of student affairs (dean of students), and/or assistant principal of academic affairs and curriculum. School nurses will also be invited if any and if possible.

The sample size of a content validity study is related to a satisfactory content validation index (CVI) that is applied to assess the content validity of each item of the intervention protocol. In this study, the CVI will be adopted to identify the required sample size and level of consensus of the expert panel. As recommended, six experts are needed to reach a satisfactory CVI of 0.83 for each item on the content validity assessment form.

Content Validity Study Procedure

A formal invitation will be delivered via telephone or email to solicit eligible experts to participate in the study. Once the experts accept the invitation, a cover letter, and the content validity assessment form will be mailed to them. The cover letter consists of the purpose of the study, the selection criteria of the expert panel, detailed information on the assessment form (the CERIA intervention protocol), and instructions for rating each item. The assessment form includes several items associated with the CERIA intervention protocol, including the intervention content (rationale of the topic, intervention approach, therapeutic principle or components of the intervention activities per session), intervention design (duration of each session, number of intervention session in total, frequency of each session, length of intervention, setting, interventionist criteria, group participants), and components of the intervention manual (a guide book for educators and another guide book for participants). The rating of each item is based on a 4-point Likert scale (4= very appropriate, 3= appropriate, 2= inappropriate, and 1= very inappropriate). If the experts scored any of the items below a score of 3, they will be asked to provide comments or suggestions with relevant evidence and references to help the study further refine the intervention protocol.

Data Analysis for the Content Validity

The item-level CVI (I-CVI) and the scale-level (S-CVI) will be applied to evaluate the content validity of each of the items and the whole CERIA intervention protocol, respectively. The I-CVI will be calculated by counting the number of experts who rate the items as "appropriate" (a score of 3) or "very appropriate" (a score of 4) and dividing that number by the total number of experts. Whereas the S-CVI will be evaluated by calculating the average I-CVI across the items. A CVI of 0.80 or higher and 0.83 are considered satisfactory values for the S-CVI and I-CVI, respectively. Any item with a low CVI will be revised based on the experts' comments or suggestions until the CVI reaches the predefined satisfactory value.

School Sample and Recruitment

Investigators will use a CONSORT flow diagram to describe the phases of this study. A purposive sampling technique will be used in this study to specifically select two public junior high schools with more than 400 students each. Data regarding the number of students at each school will be updated (in the second semester of the new academic year 2022-2023). Briefing meetings will be used to inform principals of eligible schools about the study, prior to the issuing of invitations to participate. Following this, eligibility interviews with school principals will be used to ascertain the current strategies used to promote resilience within the schools. Investigators will send an invitation letter to the school principals along with the study's information and request written consent for school participation. In the event that a school does not respond to the invitation or declines to participate, the school recruitment process will be repeated, with the next identified eligible school invited to participate. The process will be continued until two schools have been recruited.

Random Allocation of Schools

The allocation of the schools to be either the intervention or control group will be conducted using simple randomization by one of our study team members. Schools, parents of students, and enrolled students will be blinded to study group allocation.

Student Recruitment

Parent-informed consent will be required for student participation. In order to optimize parental consent for child participation, investigators will share our study information with the school community through parents' or guardians' WhatsApp groups or other existing platforms. Distribution of parental consent will be conducted in selected classrooms in the schools. Every classroom in the schools has the same probability of being chosen. Using a random number function (in Microsoft Excel), investigators will select two classrooms from each grade level to distribute the parent-informed consent along and study information. Classrooms that have been selected should be agreed upon by the school principal and classroom teachers. Within the parent study statement, investigators will provide contact information so that they can reach out if they have any questions about the study.

On the first day of student recruitment, investigators will distribute the parental consent along with the PedsQLTM 4.0 Generic Core Scale parent proxy to the students in the selected classrooms in order to be signed by their parents or guardians at home. Parents or guardians who agree to participate in the study can sign the consent form and proceed to complete the PedsQLTM 4.0, Generic Core Scale parent proxy directly. Those who do not wish to participate may leave the parent proxy field blank. Whether they agree or disagree that their child should participate in the study, all of them must return the consent form and the PedsQLTM 4.0, Generic Core Scale parent proxy to the research team the following day. Parents or guardians who do not return the parental consent will be contacted through a phone call to provide verbal consent or non-consent for their child to participate. For those who provide verbal consent, replacement study information (with parental consent) will be provided by mail. Additionally, informed student consent for participation, or a student consent form, is required from each participant prior to the completion of student surveys at each point of data collection. Hence, for students whose parents or guardians have agreed and returned the parental consent form, investigators will request that they complete and return a signed consent form.

Sample Size

Investigators use the G*Power sample size calculator under an F test with an analysis of variance based on some criteria. First, an effect size of 0.3-0.4 (medium) is used. Second, investigators used a two-tailed hypothesis testing, with an α error probability of 0.05, and a power of 0.95. Third, the number of groups is 2 (intervention and control groups), and the number of measurements is 3 (pre-test, post-test, and follow-up). The sample size from the calculator yields 100 participants in total, plus a 10% attrition rate from the total participants. Hence, our study should include at least 110 participants that will be divided into intervention (n= 55) and control groups (n= 55).

Baseline Data Collection Procedure

On the same day of the student consent form distribution, students who agree to participate will be requested to complete a sociodemographic characteristic questionnaire and the six outcome measures. However, the completion of the six outcome measures will be conducted over a two-time period on the same day to avoid boredom among the participants. In the first period, a sociodemographic questionnaire, CRIES-13, MSPSS, CYRM-28, and PedsQLTM 4.0 Generic Core version will be completed. The JCS completion will be conducted later in the second period at a time agreed upon by the researcher and participants. For students who are unable to present during the data collection, an online version of the measures will be provided. All of the data will be collected by data collectors who are blinded to the group allocation.

Intervention Delivery

Students who agree to participate will be randomly grouped; one group consists of 5-10 students. Investigators will set a schedule for the intervention sessions for all of the groups. On the following week, when the first session of the intervention will begin, an interventionist will deliver the CERIA for 45-60 minutes in a classroom setting. The session will be assisted by two research assistants who are responsible for shifting the groups. Sessions 1-6 will be repeated using the same format. Intervention attendance lists for each session containing the names of participants will be provided. Adherence to the intervention session is defined as all participants following the protocol and receiving treatment as allocated. Each participant who is unable to attend one of the intervention sessions will be provided with an online version of the session material for the session they missed. The interventionist will ask them to read the material and practice the exercises at home so they can easily get into the next session.

Post-test and Follow-up Data Collection Procedure

In the last session of the intervention, investigators will conduct an additional 30-45 minutes for a focused-group discussion in order to collect the participants' views about CERIA. A questionnaire about the participants' perspectives will also be distributed. Data collection for the secondary outcomes one week after intervention and one month after intervention will be conducted using the same format as the baseline data collection.

Interventionist

Only health professionals with at least a baccalaureate nursing degree are qualified to conduct the intervention. Reading and understanding the intervention manual is required for those who intend to deliver the intervention. In this study, only one interventionist (the principal investigator) from the research team will deliver the intervention sessions.

Intervention Development

The foundations of the intervention development were based on the adolescent disaster survivor's resilience model. In the model, pathways to predict resilience were identified. First, PTSD symptoms and defensive coping as risk factors predicted resilience in a negative pathway directly and indirectly. Second, social support and courageous coping as protective factors predicted resilience in a positive pathway also directly and indirectly. And, third, there was an indirect effect of PTSD symptoms on resilience through defensive and courageous coping. Major impacts on resilience in the model had been demonstrated by the roles of coping variables where defensive and courageous coping acted as mediators and helped explain the indirect effects between PTSD symptoms and resilience. Defensive and courageous coping reflected cognitive appraisals used by individuals to evaluate stress. Defensive coping started out as a protective mechanism followed by social support, which caused defensive coping to transform into courageous coping. In this process, social support also performed a critical role to enhance resilience. Hence, the intervention component in this study will address the roles of risk (stress and negative coping) and protective (social support and positive coping) factors in the development of resilience and health-related quality of life related to the COVID-19 pandemic.

Plan for Data Management/ Analysis

The collected data will be analyzed using IBM SPSS for Windows version 26 and assumed a statistical significance level of p ≤ 0.05. Data consistency checks will be conducted to verify the reliability of the data collected. In case of missing data, several approaches will be used depending on which type of missing data is: missing completely at random, missing at random, or missing not at random. Investigators may employ complete case analysis to overcome the missing completely at random because this suggests investigators drop all cases if investigators have one or more values missing in any of the variables required for analysis. Multiple imputations can also be used; in each dataset, the missing values will be replaced by values that are randomly sampled from the predictive distribution of the observed data. This approach will provide valid results when the data are missing at random while avoiding the loss of power (sample size reduction). Alternatively, single imputation will be used by replacing a single value that best represents the mechanism of the missing value; this could be the mean of a normally distributed continuous variable, mode or median of a categorical variable, a predicted value of a regression equation, or the last/ best/ worst observation carried forward.

Data from the feasibility and acceptability (primary outcomes) will be analyzed quantitatively and qualitatively. Quantitative analysis which will be specified to descriptive statistics analysis will be applied for data regarding the time required to recruit target participants, participant recruitment, participant retention, participant attrition rates, participant compliance with the intervention, participant compliance and completeness of evaluation measures at pre-test, participant compliance and completeness of evaluation measures at post-test, and participant compliance and completeness of evaluation measures at follow-up.

Qualitative analysis will only be applied to primary outcomes data regarding the acceptability measure: participants' perspective on the intervention, an exit survey, and interventionist' perspective on the intervention). A focus group discussion (FGD) from a selected group of participants will be conducted and the FGD will be recorded using an encrypted digital audio recorder and will be transcribed verbatim. All data will be analyzed thematically using a Theoretical Framework Analysis (TFA) to guide the analysis. The TFA consists of seven component constructs: affective attitude, burden, perceived effectiveness, ethicality, intervention coherence, opportunity costs, and self-efficacy. Our research team will conduct the analysis with regular consensus meetings.

For the secondary outcomes, a generalized estimating equation framework will be used to analyze the matched cohort of students that participate in three-time point of assessments: pre-test, post-test, and follow-up surveys, and participants lost at follow-up, on baseline demographic characteristics (gender, ethnicity, and living arrangement) and the six outcomes (CRIES-13, JCS-defensive coping, JCS-courageous coping, MSPSS, CYRM-28, PedsQLTM 4.0 Generic Core version). Additionally, a linear mixed model with fixed- and random effects will be carried out for sensitivity analysis for all secondary outcomes using intention-to-treat principles, whereby multiple imputations were used to assess the sensitivity of the results to missing data under the missing at random (MAR) assumption for students that are lost to follow-up. The fixed effect will be applied to the treatment group (intervention vs. control) and prognostic variables (age, gender, ethnicity, and living arrangement). Whereas the random effect will be applied to schools to account for the clustering of responses within schools. This analysis is aimed to analyze data on the mean differences between all participants from experimental and control groups who completed the pre-test, post-test, and follow-up surveys for all secondary outcomes.

Interim Analysis and Stopping Guideline

During the study and subsequent follow-up data collection, investigators do not expect any issues that would be harmful to the participants. Investigators have no established termination criteria, and investigators do not plan to perform interim analyses before the follow-up data collection is completed.

Inclusion Criteria:

• being aged 12-18 years old
• being enrolled in the participating public junior high schools in Yogyakarta
• voluntarily agreeing to participate by completing both the student-assent and parent-informed consent forms

Exclusion Criteria:

• individuals with mental retardation, psychosis, or any neurological disorders

Particular data will be shared: Individual participant data that underlie the results reported in this article, after identification (text, tables, figures, and appendices).

Beginning 9 months and ending 36 months following article publication.

Investigators whose proposed use of the data has been approved by an independent review committee ("learned intermediary") identified for this purpose. For example, for meta-analysis study.