Covid-19 The pressure of the CCAA on the use of AstraZeneca forces Health to give an answer in a week
Side effects Alternating doses of different vaccines increases mild reactions
Live Coronavirus, Spain, today
For weeks, both the
European Medicines Agency
(EMA) and independent experts in epidemiology and public health claim that the most appropriate thing would be to complete the vaccination schedule for people under 60 years of age who have already received a dose of AstraZeneca with another 'prick 'of the same vaccine.
"There is no data that the second dose increases the risk of thrombi.
The recommendation continues to be to administer the second dose,
" Marco Cavaleri, head of the European body's Strategy for Vaccines and Health Threats, stressed again this Wednesday.
The administration of the AstraZeneca vaccine in this population (in Spain it is mainly teachers and members of the State Security Forces and Corps) was stopped after the
detection of rare cases of thromboembolic problems
associated with the administration of the first dose of the vaccine.
During this time, several countries - such as France and Germany - have chosen to complete the vaccination with other vaccine formulations (such as Pfizer), while in the case of Spain it was decided to launch a study on the suitability of this combination beforehand.
However, authorized voices have been recalling for weeks that the most logical, sensible and adjusted to the available scientific evidence would be to complete the vaccination with another dose of AstraZeneca since the adverse effects detected correspond to an autoimmune reaction that, by definition, only appears in vulnerable people after the administration of a first dose,
never after the second 'prick'
.
The data available to date show that the few cases of clotting problems that have been associated with the administration of the AstraZeneca vaccine have occurred "after the first dose",
in no case after having completed the vaccination regimen, he
stressed. Federico Martinón-Torres, member of the Vaccine Advisory Committee of the World Health Organization and head of Pediatrics at the Hospital Clínico Universitario de Santiago a few days ago
Martinón-Torres recalls that, although the causes of this possible link between thromboembolic problems and vaccines such as AstraZeneca's are still being investigated, it is possible that, as the EMA has pointed out, it is due to an
autoimmune reaction
similar to thrombocytopenia heparin-induced (HIT) that occurs in vulnerable people.
"For this reason, when this reaction occurs, it appears after the first dose. If you have that vulnerability, it will be revealed in the first dose. If not, it is because you do not have that vulnerability," he remarks.
"It seems remote to me that it occurs in a second dose."
"
Public Health
has the power to do whatever it wants, but if there are no specific data, the logical thing is to always follow the safest and easiest path, which, in my opinion, in this case would be to complete the vaccine schedule with the same vaccine", he adds, in line with what has been defended by the European Medicines Agency.
Predictably, the
National Public Health Commission
will decide next week what with these cases that are in limbo, as indicated this Wednesday by the Minister of Health, Carolina Darias, who announced that the body "will meet and give due account of the observational reports of messenger RNA vaccine use from other countries and reports of ongoing clinical trials "
The available evidence is now joined by new data showing that combining doses of different vaccines against Covid-19 multiplies the number of more frequent mild and moderate reactions with respect to following the established vaccination schedule.
This is pointed out by the first results of the
Com-Cov
study
being carried out by researchers at the University of Oxford and which has just been published in
The Lancet
magazine
.
The research began in early 2021, before the administration of the AstraZeneca vaccine was associated with rare clotting problems.
And his goal is to find out the effects of
alternating doses of different preparations
, both from the point of view of safety and the immunity that the combination provides.
The definitive conclusions of the work will not be until June, but the researchers have published preliminary results on
reactogenicity
, that is, the common and expected adverse reactions of a vaccine.
In the case of Covid vaccines, the most common reactions are fever, pain at the injection site, fatigue, muscle pain, etc.
According to these first results, the combination of Pfizer and Astra Zeneca doses generates more mild and moderate reactions -after the second dose- than administering two doses of the same vaccine (Pfizer-Pfizer or Astra Zeneca-AstraZeneca).
Either way, the researchers recall in the medical journal that these detected effects are mild, last a short time and are resolved with a pain reliever.
In no case were serious security problems recorded.
In fact, there were no hospitalizations associated with these effects.
The
most frequent reaction was the appearance of fever
.
Headaches, muscle aches, and malaise were also more commonly recorded among volunteers who received a combination of doses.
There were no differences in terms of gastrointestinal symptoms, such as nausea.
Most of the effects appeared within two days of the 'puncture' and disappeared quickly.
The use of paracetamol was helpful in alleviating these effects.
"Although this is a secondary part of what we are trying to explore through these studies, it is important that we inform people about these data, especially since several countries are considering using these mixed dose schedules," says
Matthew Snape
in the text.
, associate professor of pediatrics and vaccines at the
University of Oxford
, and principal investigator.
The study findings suggest that "mixed dose schedules could result in an increase in absences from work the day after immunization, and this is important to consider when planning immunization of healthcare workers," Snape adds, who points out that the analyzed sample was older than 50 years, so it is possible that
the reactions may be different in younger age groups
.
Conclusions on the immunity provided by the vaccine combination will be available in June, the researcher notes.
In addition to this research, other reviews are also evaluating the effects and utility of combining different vaccine formulations.
This is the case of the
CombiVacs
study
, promoted by the Carlos III Health Institute, in which
600 people under 60 years of age participate
, a sample of the more than two million people who are pending to complete their vaccination schedule with AstraZeneca after the decision of the Interterritorial Council to interrupt the process due to cases of thrombosis linked to the vaccine, despite the fact that these are very rare adverse effects.
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