Evaluation of symptoms, hematological parameter and antibodies levels among two COVID-19 vaccines recipients and control groups

Abstract

Background: SARS-CoV-2 infection causes high rates of infection and death worldwide, constituting a widespread global pandemic and representing a major public health problem. While COVID-19 vaccines are known to reduce the severity of symptoms, comparative data on vaccine types in Iraq remains limited. objective: The present study aims to estimate and evaluation of symptoms, hematological parameter and antibodies levels among two COVID-19 vaccines recipients and control groups in Basrah populations. Methodology:  A total of 277 individuals of both sexes’ adults recruited from Al-Mudaina General Hospital between November 2021 and April 2022., comprising 153 individuals as vaccinated group, 62 of them are males and 91 females with age range 18 years - 78 years, furthermore, 124 individuals as unvaccinated group, 60 of them are males and 64 females with age range 18 years-77 years, were selected Vaccinated participants received either the Pfizer vaccine (n = 117) or the Sinopharm vaccine (n = 36). Clinical symptoms, hematological parameters (white blood cell count and lymphocyte count), and IgG/IgM antibodies against SARS-CoV-2 were assessed. Polymerase chain reaction (PCR) testing was performed on symptomatic individuals. Statistical analysis included t-tests, chi-squared tests, and logistic regression, adjusting for age and sex. Results were considered statistically significant at a p-value of less than 0.05. randomly. Results: The present study showed clear significant differences between symptoms in the two studied groups. The symptoms of the disease were more among individuals in the unvaccinated group than in the individuals that received vaccines after dose 2 in vaccinated group. Hematological parameter levels were measured among studied groups. The present results showed that there were significant differences (P< 0.05) in the levels of hematological parameters between the first and second doses within the same vaccine. COVID-19 antibodies levels were measured among vaccinated group.  In general, anti-SARS-2 IgG antibodies levels had more significant than anti-SARS-2 IgM antibodies among vaccinated group. Vaccination reduced symptoms after SARS-COV-2 infection. Conclusions: Vaccination is associated with lower rates of SARS-CoV-2 infection and reduced symptom severity. While Pfizer and Sinopharm vaccines elicited humoral immune responses, protection cannot be directly inferred from antibody levels alone. Given the observational nature of the study, the findings should be interpreted as correlations, not causal inferences.