ABSTRACT
Objectives: Actual world data on vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are imperative for future immunization decisions. We studied the reactogenicity and IgG response in a cohort dually vaccinated with the ChAdOx1 nCoV-19 vaccine. Methods: This prospective study recruited 494 ChAdOx1 nCoV-19 vaccine recipients at the University Hospital KDU between January 30 and February 5, 2021, and followed up for 9 months. The two doses of the vaccine were administered 3-month apart, followed by a booster dose with the BNT162b2 (Pfizer-BioNTech) vaccine 6 months later. One-week post-vaccination surveillance ascertained the reactogenicity of the vaccine. Seroprevalence of IgG antibodies before each vaccination dose was determined using a commercially available quantitative ELISA kit (WANTAI SARS-CoV-2 IgG Quantitative ELISA Beijing China). Reactogenicity profiles after vaccination doses were compared. Association of pre-vaccination seropositivity and demographic variables with antibody levels was assessed. Results: Reactogenicity was reported by 78.5% (329/419) and 25.4% (104/410) participants after the first and second doses, respectively, with a significantly high mean total score of vaccine-related symptoms following the first dose (P = 0.015). Post-first dose seroconversion rate was 97.1%, and the immune response was more robust among pre-vaccination seropositive participants and females. Following the second dose, 100% seroconversion was observed. Subgroup analysis of 196 participants revealed persistent antibodies at nine months with a rise in the previously measured levels among 78.1% compared to 21.9% with declining titers. Antibody waning was significantly associated with pre-vaccination seropositivity (P = 0.015) and female gender (P = 0.022). Conclusions: High seroconversion rates and longevity of antibody response in the absence of serious concerns regarding reactogenicity suggest that the vaccine is immunogenic and safe. Significant antibody waning among females and pre-vaccination seropositive participants warrant further research.
ABSTRACT
BACKGROUND: Low blood pressure and associated postural symptoms are well-recognized manifestations of anaphylaxis. Nonetheless, anaphylaxis can present with high blood pressure and is rarely reported in the literature. We report an unusual presentation of anaphylaxis with severe supine hypertension and orthostatic intolerance. CASE PRESENTATION: A 43-year-old Asian female presented to the emergency department with generalized itching, hives, and postural dizziness after taking a slow-release diclofenac sodium 100 mg tablet. On admission, the patient was tachycardic with a supine blood pressure of 200/100 mmHg. She had urticaria and bilateral rhonchi. A clinical diagnosis of anaphylaxis was made. She was treated with intravenous hydrocortisone and chlorpheniramine, but intramuscular adrenaline was withheld owing to her high blood pressure. She was kept in the supine position, and her vital parameters were closely monitored. Although the respiratory and cutaneous symptoms improved with treatment, her blood pressure remained elevated. Forty minutes later, the postural dizziness recurred as she sat up on the bed and her blood pressure plummeted from 198/100 mmHg to 80/60 mmHg. She was put back in the supine position immediately, and the blood pressure was restored with three doses of intramuscular adrenaline and a fluid bolus. Her postural symptoms completely resolved after adrenaline, but her blood pressure remained elevated. Two weeks after the initial presentation, a diagnosis of essential hypertension was made, which probably had been undetected. In anaphylaxis, where the cardiovascular system is involved, a blood pressure reduction from baseline is expected in patients with preexisting hypertension. Despite cardiovascular involvement, our patients' blood pressure on presentation to the emergency department was much higher than her pretreatment ambulatory blood pressure, thus making this presentation unusual. CONCLUSIONS: Diagnosis and treatment of anaphylaxis can be delayed in patients presenting with high blood pressure. Postural symptoms should alert the clinician to cardiovascular involvement despite elevated supine blood pressure. Early treatment with adrenaline should be considered in these patients with extreme caution.
