Analysis of information sources in references of the Wikipedia article "肌肉注射" in Chinese language version.
Aspiration before injection of vaccine is not recommended, as there are no large blood vessels at the recommended immunization sites and not aspirating before injection has been demonstrated to reduce pain.
The Danish Health and Medicines Authority's guidelines have long recommended this, and now the Statens Serum Institut is following suit.
Thus, one of the hypotheses linking the vaccine to the occurrence of severe thrombosis could be an accidental intravenous injection which, in the presence of factors not fully identified, would generate a discordant immune reaction with activation of the platelets, potentially associated with a NET effect or with a decrease in the level of ACE2 on the surface of endothelial cells, leading to an increased risk of thrombosis. A simple way to overcome this hypothetical accidental intravascular injection could be to verify the absence of blood return during vaccination, which is not currently recommended by the Ministry of Health.
However, it is not recommended to aspirate before intramuscular and subcutaneous vaccine injection provided that the vaccine is placed in the appropriate place … does not involve the risk of injecting intravenously because there are no large blood vessels in these sites. Aspiration can cause the vaccination to be more painful because it takes longer to give the vaccine
Usually one does not need to aspirate before injecting a vaccine. However, in connection with the investigation of a possible association between injection of covid-19 vaccine from AstraZeneca and the occurrence of rare but severe cases of blood clots and bleeding, SSI recommends, for the time being, on a precautionary principle, to aspirate before administration. This applies to all the approved covid-19 vaccines
Aspiration before injection of vaccine is not recommended, as there are no large blood vessels at the recommended immunization sites and not aspirating before injection has been demonstrated to reduce pain.
However, it is not recommended to aspirate before intramuscular and subcutaneous vaccine injection provided that the vaccine is placed in the appropriate place … does not involve the risk of injecting intravenously because there are no large blood vessels in these sites. Aspiration can cause the vaccination to be more painful because it takes longer to give the vaccine
The Danish Health and Medicines Authority's guidelines have long recommended this, and now the Statens Serum Institut is following suit.
Usually one does not need to aspirate before injecting a vaccine. However, in connection with the investigation of a possible association between injection of covid-19 vaccine from AstraZeneca and the occurrence of rare but severe cases of blood clots and bleeding, SSI recommends, for the time being, on a precautionary principle, to aspirate before administration. This applies to all the approved covid-19 vaccines
Thus, one of the hypotheses linking the vaccine to the occurrence of severe thrombosis could be an accidental intravenous injection which, in the presence of factors not fully identified, would generate a discordant immune reaction with activation of the platelets, potentially associated with a NET effect or with a decrease in the level of ACE2 on the surface of endothelial cells, leading to an increased risk of thrombosis. A simple way to overcome this hypothetical accidental intravascular injection could be to verify the absence of blood return during vaccination, which is not currently recommended by the Ministry of Health.