High failure rate of ChAdOx1-nCoV19 immunization against asymptomatic infection in healthcare workers during a Delta variant surge.

Immunization is expected to confer protection against infection and severe disease for vaccines while reducing risks to unimmunized populations by inhibiting transmission. Here, based on serial serological studies of an observational cohort of healthcare workers, we show that during a Severe Acute Respiratory Syndrome -Coronavirus 2 Delta-variant outbreak in Delhi, 25.3% (95% Confidence Interval 16.9-35.2) of previously uninfected, ChAdOx1-nCoV19 double vaccinated, healthcare workers were infected within less than two months, based on serology. Induction of anti-spike response was similar between groups with breakthrough infection (541 U/ml, Inter Quartile Range 374) and without (342 U/ml, Inter Quartile Range 497), as was the induction of neutralization activity to wildtype. This was not vaccine failure since vaccine effectiveness estimate based on infection rates in an unvaccinated cohort were about 70% and most infections were asymptomatic. We find that while ChAdOx1-nCoV19 vaccination remains effective in preventing severe infections, it is unlikely to be completely able to block transmission and provide herd immunity.

Cardiovascular manifestations of COVID-19: An evidence-based narrative review.

The recent outbreak of coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization on March 11, 2020. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, primarily involves the respiratory system with viral pneumonia as a predominant manifestation. In addition, SARS-CoV-2 has various cardiovascular manifestations which increase morbidity and mortality in COVID-19. Patients with underlying cardiovascular diseases and conventional cardiovascular risk factors are predisposed for COVID-19 with worse prognosis. The possible mechanisms of cardiovascular injury are endothelial dysfunction, diffuse microangiopathy with thrombosis and increased angiotensin II levels. Hyperinflammation in the myocardium can result in acute coronary syndrome, myocarditis, heart failure, cardiac arrhythmias and sudden death. The high level of cardiac troponins and natriuretic peptides in the early course of COVID-19 reflects an acute myocardial injury. The complex association between COVID-19 and cardiovascular manifestations requires an in-depth understanding for appropriate management of these patients. Till the time a specific antiviral drug is available for COVID-19, treatment remains symptomatic. This review provides information on the cardiovascular risk factors and cardiovascular manifestations of COVID-19.

HCQ prophylaxis in COVID-19 did not show any QTc prolongation in Healthcare workers.

BACKGROUND: HCQ is a commonly recommended drug for the prophylaxis of COVID-19. One of its rare side-effect includes QTc prolongation. METHODS: This was a prospective, cross sectional and observational study conducted on Hydroxychloroquine (HCQ) among Healthcare Workers (HCWs) at Max Super Speciality Hospital, Saket, New Delhi, India. A 3-lead ECG (only limb leads, it does not require chest leads) was performed. The QTc cut offs were pre decided, QTC < 470 ms for males and <480 ms for females was considered within the normal limits and anything above this was regarded as QTc prolongation. RESULTS: There were 274 HCWs enrolled into the study, including 175 males and 99 females. Majority of the HCWs were young and had a mean age of 32.19 ± 9.29 years. Out of these, 218 were taking HCQ as per the Indian Council of Medical Research (ICMR) guidelines. The median cumulative dose being taken was 1600 mg and the median QTc of these participants was 390 ms in males and 391.5 ms in females. Subsequently, 33 participants were followed-up and found to have a median QTc of 389 ms and a cumulative dose of HCQ as 2000 mg. CONCLUSION: In conclusion, ours is a first study in the middle of the pandemic which showed that HCQ prophylaxis in young HCWs without comorbidities did not show any QTc prolongation.

Hydroxychloroquine and QTc prolongation in patients with COVID-19: A systematic review and meta-analysis.

BACKGROUND: Among many drugs that hold potential in COVID-19 pandemic, chloroquine (CQ), and its derivative hydroxychloroquine (HCQ) have generated unusual interest. With increasing usage, there has been growing concern about the prolongation of QTc interval and Torsades de Pointes (TdP) with HCQ, especially in combination with azithromycin. AIMS: This meta-analysis is planned to study the risk of QTc prolongation and Torsades de pointes (TdP) by a well-defined criterion for HCQ, CQ alone, and in combination with Azithromycin in patients with COVID-19. METHODS: A comprehensive literature search was made in two databases (PubMed, Embase). Three outcomes explored in the included studies were frequency of QTc > 500 ms (ms) or ΔQTc > 60 ms (Outcome 1), frequency of QTc > 500 ms (Outcome 2) and frequency of TdP (Outcome 3). Random effects method with inverse variance approach was used for computation of pooled summary and risk ratio. RESULTS: A total of 13 studies comprising of 2138 patients were included in the final analysis. The pooled prevalence of outcome 1, outcome 2 and outcome 3 for HCQ, CQ with or without Azithromycin were 10.18% (5.59-17.82%, I2 - 92%), 10.22% (6.01-16.85%, I2 - 79%), and 0.72% (0.34-1.51, I2 - 0%) respectively. The prevalence of outcome 2 in subgroup analysis for HCQ and HCQ + Azithromycin was 7.25% (3.22-15.52, I2 - 59%) and 8.61% (4.52-15.79, I2 - 76%), respectively. The risk ratio (RR) for outcome 1 and outcome 2 between HCQ + Azithromycin and HCQ was 1.22 (0.77-1.93, I2 - 0%) & 1.51 (0.79-2.87, I2 - 13%), respectively and was not significant. Heterogeneity was noted statistically as well clinically (regimen types, patient numbers, study design, and outcome definition). CONCLUSION: The use of HCQ/CQ is associated with a high prevalence of QTc prolongation. However, it is not associated with a high risk of TdP.