The recovery course in covid is variable and depends on age and pre-existing comorbidities in addition to illness severity . According to survey , the most common persistent symptoms were fatigue (53%) followed by breathlessness (43%) , then joint pains and chest pain (22%) . Regarding recovery post covid illness - systemic evaluation of long term sequelae is still lacking , but emerging data suggest potential for ongoing respiratory impairment . In Majority cases , recovery of lung sequelae is close to 80% with residual 20% damage which goes on to improve over a period of 3-4months with constant breathing exercises . In majority cases CT scan of chest would be useful when patient has dysnoea of moderate severity (limits activity of daily living eg:- Shortness of breath on climbing 1 flight of stairs , simple house keeping tasks) Also when the oxygen saturation tends to fall below 95% , CT scan is more useful to know the severity index and to step up treatment or to know prior to the impending cytokine storm . CT chest is useful for monitoring treatment and post treatment improvement . Although radiological changes takes much time to resolve when patient is clinically improved , decision to do repeat CT should hold on , unless there is worsening . Blood viral markers , usually done are Antibodies to SARS - COV 2 . Studies show Ig G antibodies are more useful than ig M and there has been cross reactivity shown to different corona virus . Ig G Antibodies tend to rise after a mean of 14 days post symptom onset . 80% cases show ig G antibodies after a period of 21days(mean) . Antibodies are only useful for surveillance and not for treatment management .