Browsing by Author "Almasoud, Abdulrahman"

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    Persistence of Anti-SARS-CoV-2 Spike IgG Antibodies Following COVID-19 Vaccines
    (Dove Press, 2022-07-29) Alharbi, Naif Khalaf; Al-Tawfiq, Jaffar A.; Alwehaibe, Amal; Alenazi, Mohamed W.; Almasoud, Abdulrahman; Algaisi, Abdullah; Alhumaydhi, Fahad A.; Hashem, Anwar M.; Bosaeed, Mohammed; Alsagaby, Suliman A.; Medicine, School of Medicine
    Purpose: This study was conducted to investigate antibody immune responses induced by BNT162b2 and AZD1222 human COVID-19 vaccines in Riyadh city, Saudi Arabia. Patients and methods: ELISA was used to evaluate antibodies, against the SARS-CoV-2 spike S1 protein, in serum samples from 432 vaccinated individuals at six time points: pre-vaccination (baseline), post-prime, post-boost, 6-months, and 1 year post-vaccination, and 3 weeks post a third dose. Virus microneutralization assay was used to confirm antibody responses in a subset of samples. Results: Anti-SARS-CoV-2 spike IgG were detected in most subjects post-prime, reached a peak level post-boost, and remained at high level at the 6-month follow-up. At 1 year post-vaccine, the antibody levels were low but increased to a significant level higher than the peak following a third dose. The third dose was given at an average of 250 days after the second dose. The virus microneutralization assay confirmed the neutralization activity of the induced SARS-CoV-2 IgG antibodies. The vaccines induced higher IgG titres at post-prime (p=0.0001) and 6 months (p=0.006) in previously infected individuals. An increased interval between prime and boost, more than recommended time, appeared to enhance the IgG levels (p=0004). Moreover, the vaccines induced higher IgG levels in younger subjects (p=0.01). Conclusion: These data provide insights and build on the current understanding of immune responses induced by these two vaccines; and support a third boosting dose for these COVID-19 vaccines.
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    Seroprevalence of SARS-CoV-2 (COVID-19) among Healthcare Workers in Saudi Arabia: Comparing Case and Control Hospitals
    (Elsevier, 2020-03) Alserehi, Haleema Ali; Alqunaibet, Ada Mohammed; Al-Tawfiq, Jaffar A.; Alharbi, Naif Khalaf; Alshukairi, Abeer Nizar; Alanazi, Khalid Hamdan; Bin Saleh, Ghada Mohammed; Alshehri, Amer Mohammed; Almasoud, Abdulrahman; Hashem, Anwar M.; Alruwaily, Amaal Rabie; Alaswad, Rehab Habeeb; Al-Mutlaq, Hind Mohammed; Almudaiheem, Abdulllah Ali; Othman, Fatmah Mahmoud; Aldakeel, Sumyah Abdullah; Abu Ghararah, Mouath Rashid; Jokhdar, Hani Abdulaziz; Algwizani, Abdullah Rshoud; Almudarra, Sami Saeed; Albarrag, Ahmed Mohammed; Medicine, School of Medicine
    Healthcare workers (HCWs) stand at the frontline for fighting coronavirus disease 2019 (COVID-19) pandemic. This puts them at higher risk of acquiring the infection than other individuals in the community. Defining immunity status among health care workers is therefore of interest since it helps to mitigate the exposure risk. This study was conducted between May 20th and 30th, 2020. Eighty-five hospitals across Kingdom of Saudi Arabia were divided into 2 groups: COVID-19 referral hospitals are those to which RT-PCR-confirmed COVID-19 patients were admitted or referred for management (Case-hospitals). COVID-19 nonaffected hospitals where no COVID-19 patients had been admitted or managed and no HCW outbreak (Control hospitals). Next, seroprevalence of severe acute respiratory syndrome coronavirus 2 among HCWs was evaluated; there were 12,621 HCWs from the 85 hospitals. There were 61 case-hospitals with 9379 (74.3%) observations, and 24 control-hospitals with 3242 (25.7%) observations. The overall positivity rate by the immunoassay was 299 (2.36%) with a significant difference between the case-hospital (2.9%) and the control-group (0.8%) (P value <0.001). There was a wide variation in the positivity rate between regions and/or cities in Saudi Arabia, ranging from 0% to 6.31%. Of the serology positive samples, 100 samples were further tested using the SAS2pp neutralization assay; 92 (92%) samples showed neutralization activity. The seropositivity rate in Kingdom of Saudi Arabia is low and varies across different regions with higher positivity in case-hospitals than control-hospitals. The lack of neutralizing antibodies (NAb) in 8% of the tested samples could mean that assay is a more sensitive assay or that neutralization assay has a lower detection limits; or possibly that some samples had cross-reaction to spike protein of other coronaviruses in the assay, but these were not specific to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).