Here is an interesting article published on Medscape regarding some emerging research on the long-term effects of Covid-19 infection. Original Article: https://emedicine.medscape.com/article/2500114-clinical?&src=WNL_mdplsnews_210108_mscpedit_infd&uac=&spon=3&impID=2947343&faf=1&#b4
Author: David J Cennimo, MD, FAAP, FACP, AAHIVS Assistant Professor of Medicine and Pediatrics, Adult and Pediatric Infectious Diseases, Rutgers New Jersey Medical School
A retrospective, single-center study from Shanghai evaluated clinical progression of COVID-19 in 249 patients. The interval from symptom onset to hospitalization averaged 4 days (range, 2-7 days) among symptomatic patients. The vast majority (94.3%) of patients developed fever. Hospitalization lasted an average of 16 days (range, 12-20 days) before discharge. The estimated median duration of fever in all febrile patients was 10 days after symptom onset. In 163 patients (65.7%), radiological abnormalities (compared with baseline) occurred on day 7 following symptom onset, 154 (94.5%) of whom improved radiologically by day 14. The median duration to negative results on RT-PCT using upper respiratory tract samples was 11 days. Viral clearance was more likely to be delayed in ICU patients. The authors concluded that most cases of COVID-19 are mild. Early viral replication control and host-directed therapy applied at later stages were essential to improving outcomes.  In collaboration with the National Health Commission of China, Liang and colleagues  developed clinical scoring at hospital admission to predict progression to critical illness (online risk calculator free for public use). The clinical scoring system was validated with data from a nationwide cohort (n = 1590) in China. In Germany, postmortem examination of ten patients with COVID-19 revealed extensive lung pathology over time with both acute and organizing components. Nonspecific and seemingly mild liver and cardiac inflammation was also found, but no CNS involvement.  A separate autopsy study of 7 lungs described widespread thrombosis and microangiopathy with evidence of severe endothelial injury. Compared with findings in patients who died of ARDS due to influenza A (H1N1), the lungs from patients with COVID-19 had significantly more microthrombi. Long COVID Syndrome As the COVID-19 pandemic has matured, more patients have reported long-term, post infection sequelae. The majority of patients recover fully but those that do not have reported adverse symptoms such as fatigue, dyspnea, cough, joint pain, and chest pain lasting weeks to months after the acute illness. Long term studies are underway to understand the nature of these complaints.  The US National Institutes of Health includes discussion of persistent symptoms or organ dysfunction after acute COVID-19 within guidelines that discuss the clinical spectrum of the disease.  The UK National Institute for Health and Care Excellence (NICE) issued guidelines on care of long-COVID that define the syndrome as: signs and symptoms that develop during or after an infection consistent with COVID-19, continue for more than 12 weeks, and are not explained by an alternative diagnosis.  An international web-based survey of respondents (n = 3,762) with suspected and confirmed COVID-19 from 56 countries tallied prevalence of 205 symptoms in 10 organ systems, with 66 symptoms traced over 7 months. The most frequent symptoms reported after 6 months were fatigue (77.7%), postexertional malaise (72.2%), and cognitive dysfunction (55.4%).  A long-term follow-up study of adults with non-critical COVID-19 at 30 and 60 days post infection revealed ongoing symptoms in two-thirds of patients. The most common symptoms included anosmia/ageusia in 28% (40/150) at day 30 and 23% (29/130) at day 60; dyspnea in 36.7% (55/150) patients at day 30 and 30% (39/130) at day 60; and fatigue/weakness in 49.3% (74/150) at day 30 and 40% (52/130) at day 60. Persistent symptoms at day 60 were significantly associated with age 40 to 60 years old, hospital admission, and abnormal auscultation at symptom onset.  A follow-up study of COVID-19 consequences in 1,733 patients discharged from the hospital in Wuhan, China after 6 months reported fatigue or muscle weakness (63%), sleep difficulties (26%), and anxiety or depression (23%) were the most common symptoms. Lung function, as measured by CT showing interstitial change and 6-minute walking distance, was less than the lower limit of normal for 22-56% across different severity scales.  A study of 55 patients from China looked at long-term pulmonary follow-up 3 months after discharge from a symptomatic COVID-19 illness. Patients’ mean age was 47 years, 42% were female, and 85% had moderate disease. Only 9 patients (16.4%) had underlying comorbidities including hypertension, diabetes mellitus, and cardiovascular diseases, but none had preexisting pulmonary disease. None of the patients required mechanical ventilation. At 3 months, 71% still had abnormal chest CT scans, most commonly showing interstitial thickening. Spirometry was also checked in all patients. Lung function abnormalities were detected in 25.5%. Anomalies were noted in total lung capacity of 4 patients (7.3%), FEV1 of 6 patients (11%), FVC of 6 patients (11%), DLCO of 9 patients (16%), and small airway function in 7 patients (12%) despite most patients having no respiratory complaints.  These data are consistent with the findings of a study of 124 patients recovered from COVID-19 after 6 weeks in the Netherlands. The mean age was 59±14 years and 60% were male; 27 with mild, 51 with moderate, 26 with severe, and 20 with critical disease. Nearly all patients (99%) had improved imaging, but residual parenchymal abnormalities remained in 91% and correlated with reduced lung diffusion capacity in 42%. Twenty-two percent had low exercise capacity, 19% low fat-free mass index, and problems in mental and/or cognitive function were found in 36% of the patients.  Public health implications for long-COVID need to be examined, as reviewed by Datta, et al. As with other infections (eg, Lyme disease, syphilis, Ebola), late inflammatory and virologic sequelae may emerge. Accumulation of evidence beyond the acute infection and postacute hyperinflammatory illness is important to evaluate to gain a better understanding of the full spectrum of the disease.  Reinfection Clinicians, infectious disease specialists, and public health experts are examining the potential for patient reinfection with the SARS CoV-2 virus.  Cases of reinfection with SARS CoV-2 have emerged worldwide.  Several cases have shown differing viral genomes tested in the patient, which suggests reinfection rather than prolonged viral shedding. A case report showed a 42-year-old male who was infected with SARS CoV-2 on March 21, 2020 following a workplace exposure. The patient had resolution of symptoms after 10 days with continued good health for 51 days. On May 24, 2020, the patient presented with symptoms suggestive of COVID-19 following a new household exposure. Upon testing via SARS-CoV-2 RT-PCR, the patient had confirmed positive COVID-19 with several potential genetic variations that differed from the SARS-CoV-2 strain sequenced from the patient in March.  In another case, a 33-year-old male in Hong Kong had contracted COVID-19 in March 2020, which was confirmed via saliva SARS-CoV-2 RT-PCR. The patient had resolution of symptoms along with two negative SARS-CoV-2 RT-PCR results by April 14, 2020. The patient experienced a second episode of COVID-19 in August 2020 following a trip to Spain. Although asymptomatic, the patient was tested upon returning to Hong Kong and tested positive via SARS-CoV-2 RT-PCR. Genomic sequencing was performed on both RT-PCR specimens collected in March and August. The genomic analysis showed the two strains of SARS-CoV-2 (from March and August) belonged to different viral lineages, which suggests that the strain from the first episode differed from the strain in the second episode.  The Collaborative Study COVID Recurrences (COCOREC) group in France reported 11 virologically-confirmed cases of patients with a second clinically- and virologically confirmed acute COVID-19 episodes between April 6, 2020 and May 14, 2020. Although, the letter does not describe confirmation with viral genomic sequencing to understand if the cases were a relapse of the initial infection or a new infection. Two cases of reinfection have emerged in the United States, a 25-year-old man from Nevada and a 42-year-old man in Virginia. These cases were confirmed by gene testing that showed different strains of the SARS-CoV-2 virus during the 2 infection episodes in each patient. In these cases, the patients experienced more severe symptoms during their second infections. It is unclear if the symptom severity experienced the second time were related to the virus or the how the patients’ immune systems reacted. Vaccine development may need to take into account circulating viral strains. [173, 177] These case reports give insight to the possibility of reinfection. Further research to determine the prevalence of COVID-19 reinfections is needed, including the frequency at which they occur and longevity of COVID-19 immunity.