Double high-dose immunoglobulin for ChAdOx1 nCov-19 vaccine-induced immune thrombotic thrombocytopenia

ChAdOx1 nCoV-19 Vaccine and Thrombosis with Thrombocytopenia Syndrome among Adults: A Systematic Review

Several vaccine-induced thrombotic thrombocytopenia syndrome (VITTS) cases have been reported after the ChAdOx1 nCov-19 vaccination. The current study systematically reviewed the reported post-ChAdOx1 nCoV-19 vaccination thrombotic thrombocytopenia cases. Their laboratory and clinical features, as well as the diagnostic and therapeutic measures, were investigated. Online databases were searched until 25 August 2021. Studies reporting post-ChAdOx1 nCov-19 vaccination thrombotic thrombocytopenia syndrome (TTS) were included. Overall, 167 cases (21-77 years old) from 53 publications were included showing a female dominance of 1.75 times. About 85% of the cases exhibited the primary symptoms within the first two weeks post-vaccination. Headache was the most common initial symptom (>44.2%), and hemorrhage/thrombotic problems (22.46%), as well as discoordination/weakness/numbness/ hemiparesis/cyanotic toes (19.6%), were the most prevalent uncommon initial symptoms. Prothrombin time (PT), D-dimers, and C-reactive protein were the most remarkable increased laboratory parameters in 50.6%, 99.1%, and 55.6% of cases, respectively. In comparison, platelet and fibrinogen were the most remarkable decreased laboratory parameters in 92.7% and 50.5% of cases, respectively. Most VITT cases presented with cerebral venous thrombosis/cerebral venous sinus thrombosis, supraventricular tachycardia, transverse sinus/cerebral thrombosis, pulmonary embolism, and cerebral hemorrhage. Anti-PF4 antibody measurement through immunoassays and functional assays were positive in 86.2% and 73% of cases, respectively. About 31% of the cases died. Early diagnosis and proper therapeutic measures are important in ChAdOx1 nCov-19 vaccine-induced VITTS patients. Therefore, experts are recommended to know the corresponding clinical and laboratory features, as well as diagnostic methods. Elucidation of the pathophysiologic mechanism of ChAdOx1 nCov-19 vaccine-induced TTS deserves further investigation.

Vaccine-induced immune thrombotic thrombocytopenia with ChAdOx1 nCoV-19 is rare in Asia

BACKGROUND

Vaccination with ChAdOx1 n-CoV-19 is associated with a rare syndrome called vaccine-induced immune thrombotic thrombocytopenia (VITT). VITT has been reported mainly in Western countries, whereas the report of VITT in Asians is sparse.

OBJECTIVES

To report a case series of VITT following ChAdOx1 n-CoV-19 in Thailand and to estimate the incidence of VITT among Asian countries.

METHODS

We retrieved the number of VITT patients and the total inoculation doses from the database of the Thai Ministry of Public Health. We performed a literature search including published articles and gray literature to estimate the incidence of VITT. The incidences of VITT by countries and respective confidence intervals were calculated.

RESULTS

By the end of August 2021, five VITT cases occurred after 15 million doses of ChAdOx1 n-CoV-19 in Thailand. The median age was 31 years, and 60% were women. The incidence of VITT is estimated at 1 in 3 million. In other Asian countries, only a few cases of VITT have been reported. The incidence of VITT is much lower than in those of Western countries, which is estimated at 1 in 100, 000. The fatality rate was 44% in this study.

CONCLUSIONS

Although the incidence of VITT in Asians is low, the mortality rate is substantially higher. We urge that public awareness of this syndrome be raised, as early recognition and appropriate treatment of this syndrome following ChAdOx1 n-CoV-19 are crucial to improve the outcome.