COVID-19 vaccine - Long term immune decline and breakthrough infections.

BACKGROUND: Since the introduction of BNT162b2 mRNA COVID-19 vaccine by Pfizer in late 2020, efficacy and immunogenicity waning of COVID-19 vaccines was reported, and decision making regarding a booster remains a top priority worldwide, a decision that should be made based on breakthrough infection rate and antibody titer decline overtime. METHODS: We conducted a 5-month longitudinal prospective study involving vaccinated healthcare personnel, who were tested monthly for antibody titer, and sampled biweekly and on clinical indication for SARS-COV-2 polymerase chain reaction (PCR), to determine antibody decline and breakthrough infection. RESULTS: 100 participants were recruited to the study. Antibody titer reached the climate after one month of the second dose of the vaccine, and declined rapidly thereafter: the median antibody levels were 895; 22,266; 9,682; 2,554 and 1,401 AU/ml in the day of the second dose, and in one month interval thereafter, respectively. In other words, four months after vaccination, the mean antibody level was 6% of the peak levels. During the study period, 4 breakthrough infections were diagnosed, 2 of which were asymptomatic, and the remaining two were mild cases; sharp elevation of antibody titer was seen after infection. CONCLUSION: Antibody titer drops rapidly one month after the second dose of the vaccine. All infections within the study period were mild or asymptomatic, after which titer elevations were seen.

An 80-year-old man with a right upper lobe opacity.

BACKGROUND AND AIMS: The differential diagnosis of a right upper lobe pulmonary opacity in an elderly afebrile patient includes infectious and malignant etiology. However, unilateral lung edema should also be included in the differential diagnosis. METHODS: Case report of an 80-year-old afebrile patient who presented with cough, dyspnea and blood-tinged sputum and had an isolated right upper lobe infiltrate on chest X-ray on whom a diagnostic work-up including computed tomography scan of the chest and echocardiography was performed. RESULTS: Bilateral alveolar opacities and pleural effusions, not apparent on the chest X-ray, and a flail posterior leaflet with severe mitral valve regurgitation were revealed. His symptoms and findings responded to diuretic treatment. CONCLUSION: Pulmonary edema should be considered in a patient with mitral valve regurgitation presenting with a unilateral lung infiltrate. Chest computed tomography scan findings consistent with heart failure and echocardiography demonstrating mitral valve regurgitation are the main clues to the diagnosis. Diuretic therapy should cause a rapid improvement of the radiologic and clinical findings.