Objectives:~To identify Measles IgG titre in SARS-COV2 infected patients .~correlate level of Measles IgG titre with the clinical severity of COVID-19 disease.~Secondary Objective To find an association of the postulated protective role of measles vaccine and SARS-COV2 infection~Criteria:~Inclusion criteria:included patients would be divided into 3 groups according to clinical severity of COVID-19 disease (mild ,moderate & severe)~All patients with confirmed COVID 19 confirmed by positive PCR . .~Any age or gender.~Exclusion criteria:~- Any patient refusing to be involved in the study.~Methods:~Informed consent will be taken from each subject~Full clinical examination.~Evaluation of Measles Antibody Titer:~The measles virus IgG antibody titer will be determined quantitatively by ELISA for quantitative determination of IgG class antibodies against Measles virus in human serum or plasma (citrate, heparin).~- Anonymous data will be retrieved from the admitted patients' files, such as:~CBC, CRP, AST, ALT, ESR, Serum ferritin & SARS CoV 2 RNA PCR swab results.~Chest X ray and/or CT chest.
The following two mechanisms that explain the ability of measles vaccine to cause partial protection against COVID-19. The first is that measles vaccine may increase the ability of the immune system to fight off pathogens other than measles due to the generated bystander immunity that would enhance the overall immunity against the new coronavirus. The second is that SARS-CoV-2 is proven to have structure similarities with measles, which may cause cross-reactivity and immunity between measles vaccines and COVID-19, leading to partial protection against COVID-19 in vaccinated subjects