Coronavirus Warning: Study Reveals That After Infection Phase, The SARS-CoV-2 Manipulates Human Host Immune System To Facilitate Its Long Term Stay
: Day by day it is emerging despite initial denials by researchers that the SARS-CoV-2 resembles an airborne version of the HIV virus that kills the human host slowly except for those that are vulnerable either due to age, a weakened immune system and the presence of various comorbidities, where the process is even faster.
A new study by Chinese researchers from Tongji hospital, Tongji Medical College at Huazhong University of Science and Technology-Wuhan shows how the SARS-CoV-2 coronavirus after the infection phase in mild, moderate or even severe patients, starts to ‘prime’ the human host immunity system so that it can remain in small viral loads in the human host without being disturbed by the host immune system.
The study findings are published on a preprint server and are being peer-reviewed. https://www.preprints.org/manuscript/202007.0719/v1
To date it is assumed that COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20 days post initial symptoms (PIS). However, the study team observed some COVID-19 patients with existing SARS-CoV-2 for more than 50 days PIS.
The study team wanted to investigate the cause of viral clearance delay and the infectivity in these patients. Demographic data and clinical characteristics of 22 long-term COVID-19 patients were collected. SARS-CoV-2 nucleic acid, peripheral lymphocyte count, and functionality were assessed. SARS-CoV-2-specific and neutralization antibodies were detected, followed by virus isolation and genome sequencing. The median age of the studied cohort was 59.83±12.94 years.
All patients were clinically cured after long-term SARS-CoV-2 infection ranging from 53 to 112 days PIS. Peripheral lymphocytes counts were normal.
Also interferon gamma (IFN-ƴ)-generated CD4+ and CD8+ cells were normal as 24.68±9.60% and 66.41±14.87%.
Interestingly however, the number of IFN-ƴ-generated NK cells diminished (58.03±11.78%). All patients presented detectable IgG, which positively correlated with mild neutralizing activity (ID50=157.2, P=0.05). SARS-CoV-2 was not isolated, and a cytopathic effect was lacking. Only three synonymous variants were identified in spike protein coding regions.
The study team concluded decreased IFN-γ production by NK cells and low neutralizing antibodies might favor SARS-CoV-2 long-term existence. Further, low viral load and weak viral pathogenicity was observed in COVID-19 patients with long-term SARS-CoV-2 infection
The study findings have numerous implications and also open the doors to lots of questions and possibilities.
One question is that considering that all the current PCR tests lack a 100 percent accuracy and sensitivity to pick up small and minute viral loads, could there be still be SARS-CoV-2 coronavirus in the human host even after so called “recovery”? Also note that often only nasal swab samples are used and not bloo
d or organ tissues from elsewhere in the body.
Another question slightly related, could there be reservoirs of the novel coronavirus in certain more difficult to access areas like certain tissues etc?
Lastly could this minute viral loads remain in the body for long and also cause damage along the way?
Is the coronavirus remaining in a dormant format and if so what could trigger reactivation?
Can it mutate while in the human host for a long time?
Are these viral loads the reason for some of the long term health complications?
There is still a lot that is not known about this novel coronavirus and we are only still learning day by day about this unique and challenging virus that originated from China.
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