# Country-Based COVID-19 DNA Sequence Classification in Relation with International Travel Policy
## 3 Results and Discussion
Therefore, correlating this policy with classification accuracy provides a preliminary insight into its effectiveness in safeguarding the country from pandemic outbreaks. Before observing the correlation, let us direct our focus to Figure 6, which provides a graphical representation of the monthly international travel policy index in each country throughout 2021. Taking a closer look at Figure 6, we noticed a consistent application of strict international travel policy by Vietnam throughout 2021, while other countries, particularly Laos, exhibited frequent changes in their restriction scale almost every month. The majority of lines overlap at an index of 75, indicating that most countries implemented bans on arrivals from some regions. Vietnam stands out as the country that implemented a total border closure for more than half of the year, while Singapore noticeably eased restrictions to only screening arrivals in the last four months of 2021. Above all, none of the ASEAN countries had completely open borders during the 2021 timeframe. Figure 5: (a) Cumulative confirmed cases per million people and (b) cumulative deaths per million people in ASEAN countries during the second half of 2021. To investigate whether the international travel policy index correlates with the accuracy of DNA sequence classification within each country, we determined the correlation coefficient between the policy index in a specific month and the classification accuracy in a subsequent month in the second half of 2021. We only considered six countries, excluding Brunei, Laos, and the Philippines due to insufficient monthly datasets. Referring to the emergence of the SARS-CoV-2 Omicron variant [29], where a new wave of infection is expected approximately every additional (up to) 4 months of virus circulation (although we cannot confirm the periodicity will be maintained), we calculated the correlation of the policy index implemented up to 4 months before the collection date of DNA sequences. For an initial observation, Figure 7 illustrates the chart of the monthly policy index implemented up to 4 months before the sequence collection date, alongside the monthly classification accuracy for each country. It is important to note that for this month-wise classification, we conducted a similar classification strategy, but the involved sequence was reduced to 200 sequences for each class with a batch size of 100. Figure 6: Monthly average international travel policy index in each ASEAN country throughout the year 2021. Figure 7: The implemented international travel policy index in ASEAN selected countries up to 4 months before the DNA sequence collection date and monthly DNA sequence classification accuracy in corresponding countries. To indicate a potential link between prior \(i\)-month policy indices and the accuracy of DNA sequences in the corresponding month, Table 6 shows diverse correlation coefficients for each country. To address the issue of a very small sample size [30], we calculated Pearson correlations between the weekly policy index and the accuracy of week-wise classification, with 25 sequences per class, in a six-months dataset. This calculation means that each entry in Table 6 results from the Pearson correlation and \(p\)-value calculation involving 24 pairs of data. Except for Indonesia, the majority of correlations demonstrated a positive trend, suggesting that, if a relationship exists, the policy index positively correlates with the classification accuracy. Utilizing the \(p\)-value with a significance level of 5%, we observed a significant relationship between classification accuracy in Vietnam and the policy implemented four months before the collection date of the DNA sequence. Here, the \(p\)-value equals 0.01, which is less than 5%, indicating that the correlation is statistically significant with a coefficient of 0.49. This suggests that the international travel policy in March positively correlates with classification accuracy in July, while the policy in April corresponds to accuracy in August, and so forth.