COVID-19 vaccination: Study sheds light on 'rare but devastating complication'
- Researchers evaluated 294 patients to understand vaccine-induced immune thrombocytopenia and thrombosis (VITT)
- Patients with low platelet counts were found to be at maximum risk
- Researchers say understanding VITT can help countries manage vaccination better
A study conducted in the United Kingdom could prove instrumental in understanding vaccine-induced immune thrombocytopenia and thrombosis (VITT), a “rare but devastating complication” associated with COVID-19 vaccination. Researchers evaluated 294 patients with median age of 48 who had received the first dose of Oxford–AstraZeneca ChAdOx1 nCoV-19 vaccine.
Of these 170 were identified as “definite” and 50 as “probable” cases of VITT depending on the onset of symptoms 5 to 30 days after vaccination, the presence of thrombosis, thrombocytopenia, d-dimer levels and the presence of antibodies.
The overall mortality was found to be 22% with odds of death increasing by a factor of 2.7 among patients with cerebral venous sinus thrombosis. The mortality rate rose to 73% among patients with platelet counts below 30,000 per cubic millimeter and intracranial hemorrhage.
The researchers concluded that patients with low platelet count and intracranial hemorrhage were the most prone to high mortality associated with VITT.
“Treatment remains uncertain, but identification of prognostic markers may help guide effective management,” according to the study published in the New England Journal of Medicine.
UK was the first country to roll out the intramuscular Oxford-AstraZeneca vaccine which uses a nonreplicating chimpanzee adenovirus ChAdOx1 as a vector in January.
Figures released by the government on Tuesday revealed that health authorities have administered a total of 86,780,455 doses among the country's population.
The vaccine was later approved by European Medicines Agency, Australian Therapeutic Goods Administration and listed for emergency use by the World Health Organization.
In March, several European countries suspended the vaccine’s use after cases of hospitalization were reported in Norway, Germany, Austria and United Kingdom 5 to 24 days after inoculation.
The patients, most of whom were healthy young persons, developed potentially life-threatening complications such as thrombosis.
Researcher Sue Pavord said the study was “hugely important to other countries" as it would help ramp up vaccination "if they can recognize this condition and manage it promptly.”