A comparison between Pfizer/BioNTech's and Sinopharm's SARS-CoV-2 vaccines

The coronavirus disease 2019 (COVID-19), which is caused by infection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to affect the wellbeing and quality of life of people worldwide. Several different COVID-19 vaccines are currently available to combat this pandemic, some of which include messenger ribonucleic acid (mRNA) vaccines and classic inactivated virus vaccines.To get more sinopharm latest news, you can visit shine news official website.

All COVID-19 vaccines act by activating the innate and adaptive immune responses. Adaptive immunity involves the activation of B-cells, which multiply and increase in response to vaccines to ultimately support the production of antibodies.

Most COVID-19 vaccines are designed to elicit spike protein-specific antibodies, as these have been reported to be effective in combating the disease. Further, anti‐spike protein receptor-binding domain (anti‐S‐RBD) immunoglobulin G (IgG) levels play a role in determining immunity to SARS-CoV-2. The antibody titers elicited by COVID-19 vaccines can be measured using serological diagnostic tests.

In a recent study published in the journal vaccines, researchers compare antibody titers elicited by the Pfizer‐BioNTech mRNA vaccine and the classic inactivated virus vaccine Sinopharm in order to identify the most effective vaccine. This study explored both IgM and IgG antibody titers; however, the researchers concentrated more on IgG, as it has been reported to be the most prevalent antibody in human plasma that plays a role in long-term immunity conferred by vaccinations. The findings from this study may help enhance the existing vaccine therapies for COVID-19.
The current study was performed on Jordanian adults and was conducted between March and April 2021 as a prospective observational cohort study. The participants consisted of individuals who had received two doses of either Sinopharm or Pfizer‐BioNTech COVID‐19 vaccines, with an interval of 21 days. All participants were enrolled in the study six weeks after the second dose.

IgG and IgM levels in human serum or plasma specific for SARS‐CoV‐2 were measured using Vitek Immuno Diagnostic Assay Systems, which is an enzyme-linked immunosorbent assay (ELISA).The group of participants receiving either Pfizer‐BioNTech or Sinopharm vaccines was compared based on demographic characteristics, past medical history, and prior COVID-19 infections.

A total of 141 participants received the Pfizer‐BioNTech COVID‐19 vaccine, of which 93% exhibited positive IgG titers. Comparatively, 147 received the Sinopharm vaccine, of which 85.7% showed positive IgG titers.The mean titer for IgG amongst the Pfizer‐BioNTech vaccine group was 515.5 ± 1143.5 BAU/mL, and the Sinopharm vaccine group was 170.0 ± 230.0 BAU/mL. No statistically significant difference was observed in IgG positivity or IgM titers between the two vaccine groups.

Age-related differences were apparent between individuals in the IgG positive and negative groups, with 86.4% of those with negative IgG titers aged more than 60 years. Among the subjects who were administered the Sinopharm vaccine, 90.5% of those with negative titers were aged more than 60 years, whereas 9.5% were between 40-60 years old.

Notably, only one subject in the 20-40 year age group showed negative IgG titers amongst the Pfizer-BioNTech group. Further, it was observed that 54.5% of subjects who had negative IgG titers had diabetes and 40.9% were suffering from cardiovascular or cerebrovascular diseases.IgM titer positive and negative groups of individuals were also compared six weeks after vaccination based on characteristics like age, gender, body mass index (BMI), smoking habits, and positivity for IgG titers. These groups exhibited significant differences in mean IgM and IgG titer values.

Multivariable regression analysis was performed, which revealed that Pfizer‐BioNTech vaccine administration had a statistically significant positive effect on IgG titer positivity. Comparatively, the presence of cardiovascular diseases had a statistically significant negative effect.