​The World Health Organization (WHO) has warned about rare side effects associated with COVID-19 vaccines. Specifically, the AstraZeneca vaccine may cause thrombosis with thrombocytopenia syndrome (TTS), which involves blood clot formation accompanied by a decrease in platelet count. However, WHO emphasizes that this is a very rare side effect, and the benefits of vaccination with AstraZeneca in protecting against COVID-19 far outweigh this risk. ​

In Vietnam, the Ministry of Health has administered over 266 million doses of COVID-19 vaccines, including approximately 70 million doses of AstraZeneca.

Thanks to widespread vaccination campaigns, AstraZeneca and other vaccines have effectively controlled the pandemic, significantly reducing COVID-19 morbidity and mortality rates. ​

For individuals who have received the AstraZeneca vaccine, the Ministry of Health states that the risk of developing thrombocytopenia syndrome typically appears within a short period after vaccination, and there is currently no such risk for those who were vaccinated nearly a year ago.

Therefore, there is no need to perform blood clotting tests such as D-dimer.

Additionally, some studies have reported other rare side effects related to COVID-19 vaccines. For example, a study in Hong Kong found that for every 1 million doses of the Pfizer-BioNTech vaccine administered, there were approximately 7 cases of severe herpes zoster (shingles) requiring hospitalization.

However, health experts assert that serious side effects of COVID-19 vaccines are very rare, and the benefits of vaccination in preventing COVID-19 and its severe complications far outweigh these potential risks.

​Novak Djokovic, the Serbian tennis champion, has consistently upheld his personal beliefs regarding COVID-19 vaccination, even when it impacted his participation in major tournaments.

He emphasizes the importance of individual autonomy over one’s body, stating, “I understand that being unvaccinated today, I’m unable to travel to most of the tournaments… that is the price I’m willing to pay. The principles of decision making on my body are more important than any title, or anything else.” ​

This stance led to significant consequences in 2022. Djokovic was deported from Australia, preventing his participation in the Australian Open, due to his unvaccinated status.

Similarly, he was barred from entering the United States, missing tournaments like the US Open.

Despite these setbacks, Djokovic remains steadfast in his decision. In a 2023 interview, when asked if he regretted not getting vaccinated, he expressed no remorse, highlighting his commitment to personal choice over professional opportunities. ​

In early 2025, Djokovic revealed that during his detention in Melbourne in 2022, he suspected being exposed to food containing high levels of lead and mercury, leading to severe flu-like symptoms.

However, he harbors no resentment and continues to focus on his tennis career.

Throughout these challenges, Djokovic’s dedication to his principles and his sport remains unwavering.