TEMPO.CO, Jakarta - A post claiming that Covid-19 vaccine recipients must undergo a D-dimer blood clotting test circulated on Instagram [archive] on December 5, 2025. The D-dimer test is used to detect blood clots.
The content included a video of a man citing research in the Lancet journal that found 74 percent of people died suddenly due to brain clots after receiving the Covid-19 vaccine. "The Covid vaccine thickens our blood, causing flesh to form in our veins," the man said. The post was liked 4,100 times and received 500 comments.
This article will verify two claims. First, is it true that someone who has received the Covid-19 vaccine must undergo a D-dimer test to detect blood clots in the brain? Second, has the Lancet journal ever published research regarding a 74 percent rate of sudden deaths due to the Covid-19 vaccine?
FACT CHECK
Tempo's Fact Check Team verified this claim by interviewing doctors and searching credible research journals. The results showed that someone who has received the Covid-19 vaccine does not need to undergo a D-dimer test. The medical journal The Lancet has also never published research claiming a 74 percent rate of sudden deaths due to the Covid vaccine.
Claim 1: Someone who receives the Covid-19 vaccine must undergo a blood clot test
Dr. Ari Baskoro, SpPD, K-AI, FINASIM, a lecturer in the Department of Internal Medicine, Division of Allergy-Clinical Immunology, Airlangga University, explained that the Covid-19 vaccine, like other vaccines, has medical events that occur after immunization that are suspected to be related to the vaccine. This term is called adverse events following immunization (AEFI). Vaccine adverse events (AEFI) can range from mild to severe, with rare occurrences.
Ari explained that one of the severe AEFI from the Covid-19 vaccine is blood clotting, or vaccine-induced immune thrombotic thrombocytopenia (VITT). However, this is rare with mRNA-based Covid-19 vaccines, such as those produced by Pfizer/BioNTech and Moderna.
According to Ari, globally, these blood clotting cases are extremely rare. "The incidence is only around two to 15 cases per million vaccinations; it's extremely rare," Ari told Tempo on Wednesday, December 17, 2025.
The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have also confirmed that the benefits of the Covid-19 vaccine far outweigh these adverse events.
Therefore, people who have been vaccinated against COVID-19, including those who received the AstraZeneca or Johnson & Johnson vaccines, do not need to undergo routine D-dimer testing. This is because blood clotting only occurs between four and 42 days after vaccination.
"If it's longer than that, blood clots definitely won't occur," he said.
Claim 2: The Lancet journal published a 74 percent rate of sudden deaths after receiving the Covid-19 vaccine.
The immunology expert also explained that the Lancet Journal never published research on the 74 percent sudden death rate associated with the COVID-19 vaccine. "Instead, the Lancet published a study demonstrating the vaccine's effectiveness in preventing the adverse effects of COVID-19," he said.
According to the Paris-based fact-checking organization, Lead Stories, the Lancet initially published an article claiming 74 percent sudden death rates were due to the COVID-19 vaccine, titled "A Systematic Review of Autopsy Findings in Deaths after COVID-19 Vaccination."
In the research methods section, the authors stated that they conducted a systematic review of all published autopsy and necropsy reports related to COVID-19 vaccination through May 18, 2023, using the PubMed and ScienceDirect databases.
However, 24 hours later, the Lancet removed the article. In its official statement, the Lancet explained that the article violated its criteria because the study's conclusions were not supported by clear methodology. According to the Lancet, the article was still in preprint or draft form and had not yet undergone formal peer review.
While an article is still a preprint, its findings should not be used to inform clinical decisions or public health policy. "Articles should not be presented to the general public without emphasizing that the findings are preliminary and have not yet undergone peer review," the statement reads.
CONCLUSION
Based on Tempo's investigation, the claim that the D-dimer test is used to detect blood vessel blockages caused by the COVID-19 vaccine is false.
A D-dimer test is unnecessary, especially routinely, for anyone who has been vaccinated against COVID-19. This is because the timeframe for blood clots to occur is only 4 to 42 days after vaccination.
Similarly, the Lancet journal never published research on the 74 percent sudden death rate associated with the COVID-19 vaccine.
TEMPO FACT CHECK TEAM
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