A strategy based on a few robust studies, but noted that it is a way to prevent people from taking the second dose due to a deficiency of the fortifying agent at a particular immunization site. Vaccination with various means of immunization has become a reality in countries such as Italy, the United Kingdom, Canada, Germany and South Korea.
The United Kingdom was one of the pioneers in the initiative. The UK Medicines and Health Products Regulatory Agency notes that studies are being done on immunogenicity in cases where different medicines are used. However, the agency recognizes the possibility of exchanging immunizing agents.
“Every effort should be made to determine which vaccine the individual received for his first dose and to complete the two-dose schedule of the same vaccine. For individuals who have started the schedule and who are attending for vaccination in a location where the same vaccine is operating is not available, for example, if the individual received his first dose abroad, or If the first product received is unknown, then it is reasonable in these circumstances to provide a dose of locally available product to complete the schedule,” the agency’s technical officer notes.
Reasons for change
Elsewhere in Europe, the reason was another. Countries such as France, Spain and Germany choose a second dose of a different vaccine for those who have received an injection of AstraZeneca.
The change includes concerns about thrombosis (considered rare) in certain populations, especially people under the age of 60.
German Chancellor Angela Merkel recently took a dose of Moderna after initially vaccinating her with AstraZeneca.
Even without consensus in the scientific community, the European Medicines Agency said last Wednesday (23) that there is a “good scientific basis” to suggest that the combination of immunity against Covid-19 is safe and effective.
The European regulator’s justification is that all of the two-dose vaccines used in the block – Pfizer/BioNTech, Moderna and AstraZeneca – work in a similar way, focusing on the thorny protein of the coronavirus.
However, the EMA notes that it is currently “not in a position to make definitive recommendations on the use of different covid-19 vaccines for the two doses.”
Studies in the UK have already released preliminary safety data. AstraZeneca and Pfizer vaccines were analyzed.
Preliminary interaction and safety data from the Com-COV2 clinical trial showed that trial participants who received different vaccines for the first and second dose experienced an increased rate of reactions after the second dose compared to those who received the same vaccine for both doses. From the mixed vaccines, they were more likely to develop fever, chills, and fever. , fatigue, headache, joint pain, malaise, and muscle aches. However, there was no in-hospital treatment for these symptoms, and the bulk of the increase in reactivity was observed within 48 hours after immunization,” says the MHRA.
The part of the study looking at the effect of mixing vaccines on immunity is expected to be released soon.
A different scenario in Brazil
In Brazil, the possibility of sharing vaccines has not yet been considered. According to Isabella Palalai, Vice President of the Brazilian Society of Immunization, “There is no reasonable reason to start with [vacina] It ends with another.”
She notes that it was possible from the start to ensure that people were vaccinated with doses of the same immunizing agent and that delivery schedules provide some assurance that this can be maintained.
* With information from Portal R7