Introduction
Coronaviruses are a large family of viruses discovered in 1960 that can cause the common cold. Coronavirus disease 2019 (COVID-19), induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in December 2019, and the number of affected countries grew rapidly, prompting the World Health Organization to disclose it as a pandemic in 2020. Almost all of the COVID-19 patient populations are clinically silent or have mild to severe respiratory illness. However, death cases involving sub and systemic manifestations such as sepsis, septic shock, and multiple organ dysfunction syndromes (MODS) have been reported. (1)
The pandemic had caused more than 629 million cases and 6.58 million confirmed deaths as of October 27, 2022, helping to make it one of the toughest in history. (2)
From 3 January 2020 to 5:43 pm CEST on 28 October 2022, there were 2,461,107 known cases of COVID-19 in Iraq, with 25,358 fatalities, according to WHO data. A total of more 19,394,050 vaccine doses has been delivered as of Oct 22, 2022. (3)
The cytokine storm is critical in the pathophysiology of severe COVID-19 patients. (4)
Cytokine storms can also be caused by a variety of viral and especially non-disorders, and they can cause serious damage to several organs. (5)
The apparent long term effects of COVID-19 on aggravating heart damage, inflammation, and plaque activity have led to the hypothesis that cholesterol metabolism may be involved and that medicines lowering all of these unfavorable outcomes might be helpful tools for COVID-19 therapy. In this context, the pleiotropic benefits of statins (beneficial effects beyond cholesterol-lowering) include anti-inflammatory, immunomodulatory, and antithrombotic qualities, all of which are observable before lipid-lowering is visible. (6)
Studies have shown that CRP levels are important inflammatory markers which need to be studied in this disease. The findings might be extremely useful in designing treatments for specific patients and following up on them. (7)
Lymphocyte counts have been used for differential diagnosis in COVID-19 patients and are an important indicator. A recent meta-analysis shows that those with lymphopenia have a 3-fold higher risk of developing severe COVID-19. Lymphopenia is a prominent feature of COVID-19 and lymphocyte counts may be a useful, easily available biomarker in predicting the severity and clinical outcomes. (8)
Immunoglobulins IgM and IgG have an important role in confronting viral diseases and are important markers for diagnosis Additionally, IgG, IgM-specific antibodies targeting SARS-CoV-2 can also be found in the majority of patients. Clarifying these immune-pathological variations might indicate potential targets for immunotherapy and is important for specialists in selecting the appropriate therapeutic care. (9)
However, despite numerous clinical studies and meta-analyses, any reliable prognostic method that can predict patient progression to severe disease based on cytokine levels at admission remains imprecise. Studies have shown that higher inflammation and specific cytokine profiles contribute to disease severity. Multivariate comparisons showed that TNF-, IL-2, IL-6, IL-10, IL17, and CRP were statistically different, while IFN and IL-4 were not. (10)
The COVID-19 pandemic’s global scope makes the need for a vaccine more urgent than ever, in contrast to SARS and MERS, which often resolve on their own after a local epidemic. Numerous diverse methods of vaccine development have been adopted as a result of this pressing necessity. First of all, because of their capacity to be generated using just sequence information, novel vaccination platforms, such as nucleic acid vaccines and viral vector vaccines, are quickly rising to the top of the COVID-19 vaccine development field. (11) Mortality rates of COVID-19 have diminished in vaccinated individuals and societies with higher vaccination rates have demonstrated lower mortality. Vaccination has been shown in several studies to reduce morbidity and death. According to an Italian study, the risk of SARS-CoV-2 infection, hospitalization, and mortality gradually reduce after the initial two weeks. (12)
Although many clinical studies have been performed during the COVID-19 pandemic, however due to the continuing spread of the disease in many countries and the diverse manifestations and mortality rates it is necessary to elucidate the immune pathways involved for better diagnosis and therapy and long term follow up.
In this work we studied the relationship between CRP and cholesterol levels, lymphocyte counts and detection of IgM and IgG with IL6, IL10 and IL17 levels and compared them in vaccinated and unvaccinated healthy and COVID-19+ patients in Iraq.