Risk factors of SARS-CoV-2 infection in cancer patients pre- and post-vaccination.

BACKGROUND: Severe complications from COVID-19 and poor responses to SARS-CoV-2 vaccination were commonly reported in cancer patients compared to those without cancer. Therefore, the identification of predisposing factors to SARS-CoV-2 infection in cancer patients would assist in the prevention of COVID-19 and improve vaccination strategies. The literature lacks reports on this topic from the Kingdom of Saudi Arabia (KSA). Therefore, we studied clinical and laboratory data of 139 cancer patients from King Abdulaziz Medical City, Riyadh, KSA. METHODS: The cancer patients fall into three categories; (i) uninfected with SARS-CoV-2 pre-vaccination and remained uninfected post-vaccination (control group; n = 114; 81%), (ii) pre-vaccination infected group (n = 16; 11%), or (iii) post-vaccination infected group (n = 9; 6%). Next, the clinical and lab data of the three groups of patients were investigated. RESULTS: Comorbidity factors like diabetes and hemodialysis were associated with the risk of infection in cancer patients before the vaccination (p<0.05). In contrast to breast cancer, papillary thyroid cancer was more prevalent in the infected patients pre- and post-vaccination (p<0.05). Pre-vaccination infected group had earlier cancer stages compared with the control group (p = 0.01). On the other hand, combined therapy was less commonly administrated to the infected groups versus the control group (p<0.05). Neutrophil to lymphocyte ratio was lower in the post-vaccination infected group compared to the control group (p = 0.01). CONCLUSION: Collectively, this is the first study from KSA to report potential risk factors of SARS-CoV-2 infection in cancer patients pre- and post-vaccination. Further investigations on these risk factors in a larger cohort are worthwhile to draw a definitive conclusion about their roles in predisposing cancer patients to the infection.

Outcomes of single dose COVID-19 vaccines: Eight month follow-up of a large cohort in Saudi Arabia.

BACKGROUND: Two vaccines for COVID-19 have been approved and administered in the Kingdom of Saudi Arabia (KSA); Pfizer-BioNtech BNT162b2 and AstraZeneca-Oxford AZD1222 vaccines. The purpose of this study was to describe the real-world data on the outcome of single dose of these COVID-19 vaccines in a large cohort in KSA and to analyse demographics and co-morbidities as risk factors for infection post one-dose vaccination. METHODS: In this prospective cohort study, a total of 18,543 subjects received one dose of either of the vaccines at a vaccination centre in KSA, and were followed up for three to eight months. Data were collected from three sources; clinical data from medical records, adverse events (AEs) from a self-reporting system, and COVID-19 infection data from the national databases. The study was conducted during the pandemic restrictions on travel, mobility, and social interactions. RESULTS: The median age of participants was 33 years with an average body mass index of 27.3. The majority were males (60.1%). Results showed that 92.17% of the subjects had no COVID-19 infection post-vaccination as infection post-vaccination was documented for 1452 (7.83%). Diabetes mellitus 03), organ transplantation (p = 0.02), and obesity (p < 0.01) were associated with infection post-vaccination. Unlike vaccine type, being Saudi, male, or obese was associated with the occurrence breakthrough infections more than other parameters. AEs included injection site pain, fatigue, fever, myalgia, headache and was reported by 5.8% of the subjects. CONCLUSION: Single dose COVID-19 vaccines showed a protection rate of 92.17% up to eight months follow-up in this cohort. This rate in AZD1222 was higher than what have been previously reported in effectiveness studies and clinical trials. Obese, male, and Saudi were at higher risk of contracting the infection post-vaccination, Saudi and male might have more social interaction with the public when mobility and social interactions were limited during the pandemic. Side effects and AEs were within what has been reported in clinical trials.