Chilean health authorities Thursday decided to halt until further notice the anti-covid-19 vaccination of people under 45 years of age with the second dose of the Oxford-AstraZeneca immunizer following the occurrence of one case of thrombosis and thrombocytopenia.
The case was detected in a 31-year-old man, who is in good health, since the condition would not have been serious, it was reported. The Chilean Institute of Public Health analyzed what happened and will publish the results of its investigation shortly.
“We are awaiting the result of an investigation. Tomorrow the Public Health Institute (ISP) will give the result of whether or not there was an adverse effect in a 31-year-old patient,” Health Minister Enrique Paris said.
Meanwhile, “as a preventive and proactive measure, while the Public Health Institute performs the causality analysis, it has been decided as a health authority to modify the age of administration of this vaccine, starting at 45 years, until obtaining the results of said investigation,” Paris added.
Chile began this Thursday to vaccinate 23-year-olds and will continue the advance of immunization with CanSino, Pfizer and Sinovac in the coming days.
It was also reported that 11 people Thursday fainted in the municipality of Las Condes, in Santiago after receiving the CanSino vaccine, and another 20 reported extreme fatigue. In total, 770 doses of this vaccine were applied, which, being a single dose product, doubles the viral load, due to which these situations fall within what is expected may happen after being inoculated.
The reason that the AstraZeneca vaccine can cause thrombosis is in a small protein called platelet factor 4 (FP4), according to two investigations published in The New England Journal of Medicine. In the very rare cases in which the immune system generates antibodies against this protein platelet factor 4, “a phenomenon of thrombosis occurs accompanied by a paradoxical decrease in the number of platelets in the blood, which are the components that form clots,” the journal explained.
However, once the phenomenon is detected in time, the appropriate treatment can “dissolve the thrombi and solve the problem without sequelae,” it added.
The Oxford AstraZeneca vaccine is currently applied in 135 countries. After vaccination was suspended in different European countries, the EU Medicines Agency (EMA), analyzed the cases and gave the green light to the safety of the vaccine.
In April, Chilean health authorities approved the use of the AstraZeneca vaccine in women over 55 years of age and in men over 18 years, due to the cases of thrombosis detected in people inoculated with this product in Europe and other parts of the world.
Overall, Chile has received 4,136,340 doses of the US vaccine from Pfizer, 693,600 from AstraZeneca, 17,171,476 from Sinovac and 300,000 from CanSino, for a total of 22,301,416.
A total of 10,817,098 people have been vaccinated with the first dose of any of the available products and 8,086,248 have completed the immunization cycle.
Since March 11, 2020, the World Health Organization (WHO) has classified as a pandemic the COVID-19 disease caused by the new coronavirus SARS-CoV-2, detected for the first time at the end of 2019.
In Chile, 1,394,973 people have been infected, of which 29,385 died.