The doctor said that if people get a PCR test after the quarantine period, there is still the possibility of testing positive if one is infected.
Therefore, after 10 days of quarantine period, people are free to go without any strings attached.
There is no worry of them infecting others.
ご質問ありがとうございます。
"The doctor said that if people get a PCR test after the quarantine period,"＝「医者は隔離期間後にPCR検査を受けたら～だと言った」
"there is still the possibility of testing positive if one is infected."＝「感染したら陽性となる可能性がまだあると。」
"Therefore, after 10 days of quarantine period,"＝「なので、10日間の隔離期間後は」
"people are free to go without any strings attached."＝「無条件で隔離解除になる」
"There is no worry of them infecting others."＝「彼らが他の人々を感染する心配はない。」
ご参考に。
アメリカ合衆国 
