Immunological Features of COVID-19 in Hodeidah, Yemen

Background: Monitoring of the immunological status linked with coronavirus disease 2019 (COVID-19) infection in Yemen is practically absent. Several studies vary in study design, populations under study, serologic tests used, timing of sample collection, and quality.

Objective: Therefore, our study aimed to present the validation of immunological method namely rapid test for detection of immunoglobulin G (IgG) of COVID-19 infection immune response development in the blood of healthy participants )asymptomatic) were living in the COVID-19 pandemic area and of the patients who have undergone COVID-19 infection.

Methodology: Rapid test was validated that included the sensitivity, specificity, precision and accuracy parameters and used for sampling in research analysis. Participated volunteers of this study were provided written consent. The study was designed in one time cross sectional COVID-19 antibodies survey after three months of COVID-19 pandemic and implemented in four groups (N:72): the first group COVID-19 was recovered patients (n:18) that admitted in isolation department , Center of Tropical Medicine and Infectious Diseases (CTMID), Al Thawara Public Hospital Authority, Hodeidah, Yemen, the second group was contacts of severe patients (n:18), the third group was mild and moderate cases (n:18) that were treated at home ,and the fourth group was asymptomatic cases (n:18)”. Data obtained were analyzed based on appropriate statistical tools.

Results: The results of rapid test validation showed that is sensitive (85.19%; CI: 72.88 to 93.38%), specific (83.33%;CI: 58.58 to 96.42%) , precise (93.88%; CI : 68.73 – 102.52%) and accurate (86.11%; CI : 84.72 to 92.12%) for detection of IgG of COVID-19 in Hodeidah, Yemen. In total, 49 of 72 participants were rapid test positive, giving a prevalence of COVID-19 of 68.05%. The COVID-19 IgG antibodies were detected in 18/18 cases (100%) of recovered severe patients (high prevalence); 17/18 cases (94.44%) of contacts (high prevalence). In addition, IgG were detected in 11/18 cases (61.11%) of mild and moderate patients (middle prevalence) and 3/18 cases (16.66%) of asymptomatic (low prevalence).

Conclusion: The study concluded that COVID-19 IgG antibodies become detectable after symptom onset of severe cases and their contacts (high prevalence) based on validated immunological method. On the other hand, the antibodies were developed in mild and moderate patients (middle prevalence). The IgG were developed in asymptomatic patients (low prevalence). However, additional data are needed before modifying public health recommendations based on serologic test results.