Immunological Response of SARS-CoV-2 Infection
There are no translations available.

Dr Kelvin Kai-wang TO

Specialist in Clinical Microbiology and Infection
Clinical Associate Professor, the University of Hong Kong



Coronavirus Disease 2019 (COVID-19) pandemic has devastated the world in 2020.  The number of COVID-19 cases has surpassed 62 millions, with over 1.4 million deaths as of 30th November, 2020.  COVID-19 has also led to severe disruption in the socioeconomic activity.  The World Bank has forecasted a 5.2% reduction in global GDP in 20201. 

COVID-19 is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was first identified during a pneumonia outbreak in Wuhan in December 2019.  Epidemiological studies showed that SARS-CoV-2 infection has a lower case-fatality rate than that of 2003 SARS-CoV, but can transmit much more efficiently between humans2.  Seroprevalence studies showed that neutralising antibody against SARS-CoV-2 are not found in blood specimens collected before 2020 in Hong Kong3.

Understanding the immune response for COVID-19 is important for clinical practice. First, the correct interpretation of serology results requires a good understanding of the antibody kinetics during infection.  Second, although SARS-CoV-2 can infect different organs and can directly cause tissue damage, many complications of COVID-19 are related to the dysregulated inflammatory response or immune-mediated damage.  Third, understanding the immune correlates of protection is critical for risk assessment and for determining the immunogenicity of vaccines.



Similar to other infections, SARS-CoV-2 infection is accompanied by elevated levels of cytokine and chemokines.  Studies have shown that the cytokine/chemokine pattern in patients with critical illness is distinct from those with moderate disease severity [4].  Critically ill patients (those who died, required mechanical ventilation or ICU admission) had increased levels of all types of cytokines, including those from type 1 (against virus or intracellular bacteria, such as IFN-γ), type 2 (allergic or anti-helminth immunity, such as IL-5) and type 3 (against fungi or extracellular bacteria, such as IL-17) immunity.  Critically ill patients also demonstrated persistently elevated levels of cytokines, while those with less severe disease demonstrated a progressive reduction in cytokine levels after day ten post-symptom onset. Although the cytokine and chemokine levels are elevated among COVID-19 patients, the level is much lower than in other inflammatory conditions.  A meta-analysis showed that the level of IL-6 is much lower among COVID-19 patients than patients with cytokine release syndrome, sepsis or acute respiratory syndrome unrelated to COVID-195.  This observation is important and suggests that the use of different cytokine inhibitors should be carefully evaluated.


More information

地址: 香港中環畢打街1-3號中建大廈308室

電話:(852) 2868 2184    傳真:(852) 2868 3084
微訊: drying308    Whatsapp: (852) 6205 3505

antalya escort antalya escort mersin escort samsun escort kusadasi escort mersin escort adana escort eskişehir escort istanbul escort gaziantep escort bodrum escort izmir escort bursa escort kayseri escort ankara escort netspor canlı mac izle