The study ‘Combivacs‘which is being developed by the Carlos III Health Institute, dependent on the Ministry of Science and one of the bodies that advises the Ministry of Health on the management of the pandemic of the covid-19, has published this Wednesday new preliminary data on the observations that the researchers are finding in the 673 participants to those who have administered a second dose with Pfizer vaccine -based on messenger RNA- after receiving the first puncture from AstraZeneca -based on adenovirus-.
If just two weeks ago they presented the results regarding humoral immunity at a press conference, this Wednesday they announced the results regarding cellular immunity in a press release. Before reading further, it should be clarified that the immune system reacts to vaccines with two forms of defense and protection against the virus.
“The first is called humoral immunity and consists of the generation of antibodies by immune cells called B lymphocytes, which block the virus before it infects. The second is the cellular immunity, which is produced thanks to the activation of T lymphocytes, another type of immune cells that acquire the ability to destroy the cells already infected “, explains the own release of the ISCIII.
According to the new preliminary findings of the study, which have been published – without peer review yet – in the journal’s repository The Lancet, “a heterologous vaccination regimen (based on the combination of different vaccines) induces a potent humoral and cellular response against covid-19”.
On April 18, urged by the need for Health to decide what to do with those around 1.7 million essential workers under the age of 60 who had received the first dose of AstraZeneca before this vaccine, produced at the University of Oxford, was restricted to the elderly to minimize the risks of rare and very rare thrombotic events with thrombocytopenia (low platelet count) observed after the administration of AstraZeneca, the ISCIII submitted its first observations, which stated that the IGG antibody levels increased 150 times in those who had received the second dose of Pfizer (14 days prior) versus those who had received only the first dose of AstraZeneca.
A “very significant” increase in humoral immunity, “such that the antibody titers achieved are even higher than those seen with homologous vaccination (two doses of the same vaccine) in previous studies, “they recall.
Now, the researchers assure that the mixture of vaccines that the Ministry of Health has finally recommended also increases the cellular immunity, that is, the one that activates T cells capable of destroying infected cells. “The results indicate that cellular immunity is not only enhanced after the second dose of a messenger RNA vaccine in people who had previously received an adenoviral vaccine, but also, based on data published by other research, could be higher than that observed in vaccination regimens based on two doses of the same vaccine“, they assert.
According to Jordi Cano, a researcher at the National Center for Microbiology (CNM), these new preliminary results reveal that the increase in cellular immunity is “significantly greater in the group of people vaccinated with the second dose of Pfizer compared to the control group, what you only have the first dose of AstraZeneca“.
In addition, the scientist continues in the statement, “the data from CombivacS support that, while the cellular response against SARS-CoV-2 does not vary after homologous vaccination with two doses of AstraZeneca, heterologous vaccination with a first dose of AstraZeneca and a second from Pfizer induce a four times higher magnification in the production of IFN-gamma “(a protein produced by T lymphocytes that helps trigger the cellular immune response).
90% choose to repeat AstraZeneca
This information comes late for most of the essential workers who these days have to choose between Pfizer -as recommended by the Ministry- or AstraZeneca -option that was enabled in an exceptional way in order to complete the vaccination schedule-. For the moment, almost all (90%) of those under 60 years of age who are in this situation have chosen to repeat with AstraZeneca, despite the fact that the Minister of Health, Carolina Darias, urged otherwise.
This Monday, the director of the Center for the Coordination of Health Alerts and Emergencies, Dr. Fernando Simon, regretted that this issue “It has been used by politicians, the media with editorial interests and the lobbiesThis was stated when he was asked if he considered a failure or an error in communication by the Government about the controversy that arose around the second dose of AstraZeneca and after several Communities such as Madrid, Andalusia or Galicia recommended repeating this vaccine According to the indications of the technical data sheet of the vaccine and of the European Medicines Agency.