The US Centers for Disease Control and Prevention (CDC) updated the guidelines for new crown vaccination on Thursday, suggesting that the second dose can be given at most six weeks after the first dose of vaccine, and in special cases, the two doses can come from different pharmaceutical manufacturers.
At present, Pfizer and Modena are the two main vaccinations in the United States. They propose to take the second dose 21 days and 28 days apart respectively. A CDC spokesman said that vaccination should be carried out according to the manufacturer’s guidelines as far as possible. However, considering that some people may fail to take the second dose within the specified time, it is suggested that the second dose should be given at most six weeks apart in order to make the vaccination plan more flexible In case of special circumstances, such as forgetting or failing to find out the manufacturer of the first dose of vaccine, or the vaccine is no longer available, the public can get another vaccine.
British Medical Association has reservation
Some infectious disease experts said that although there is no evidence to show how long the immune effect of the first dose of vaccine can last, it is believed that it will still have a certain effect after six weeks.
The day before yesterday, the French National Health Supervision Agency (has) also proposed to extend the interval between two doses of vaccine from three weeks to six weeks, so as to let more people get the first injection as soon as possible. Earlier, in order to vaccinate more people in a short period of time, the interval was also extended to a maximum of 12 weeks due to the shortage of vaccine in the UK. However, the British Medical Association urged the authorities to reconsider the decision the day before yesterday to deal with the more infectious variant Comprehensive report