The screening followed up teaching and non-teaching staff, from several schools in Oeiras municipality, after Astrazeneca vaccination and over a period of one year. The data collection in this population and with this vaccine allowed to find out more about the immune system response and the duration of the immunity conferred by the vaccine. The project carried out by the Instituto Gulbenkian de Ciência in partnership with the Group of Health Centers of Western Lisbon and Oeiras and Oeiras Municipality focused on strengthening the epidemiological efforts.

1^st phase of the screening

The participants in the screening received the first dose of Astrazeneca vaccine (on March 27 – 28) and were tested in the weekend of April 24- 25.

The 219 participants, teaching and non teaching staff, were integrated in the initiative with the aim of evaluating the response of their immune system.

Throughout the process, periodic blood samples were collected to understand at all times how each participant responded to the vaccine and what degree of immunity they developed.

One-year follow-up revealed unknown data.

2^nd phase of the screening

The second phase of the screening took place during the weekend of June 19 -20 at Pavilhão Desportivo Carlos Queiroz, in Carnaxide. This was the second blood draw and it was carried out at the time of the administration of the second dose. The study followed up 344 participants in total.

The SARS-CoV-2 vaccine effectiveness was one of the focus points of research in the IGC, who followed since December 2020 1245 healthcare professionals  and 146 elderly living in nursing homes.

The introduction of vaccines in the population required close monitoring and surveillance, at the same time the evaluation of the Covid-19 vaccine response was little studied. Knowing this response, in different populations and in different age groups, was key to adjust vaccination policies or a possible revaccination.

Epidemiological surveillance of vaccine administration was essential to stop the pandemic.

3^rd phase of the screening

The third phase of the screening took place on 17th July (Saturday) at Fundição de Oeiras. 

Immunological response in mixed vaccination schemes

According to data from the analysis of antibody levels, of the 1905 people vaccinated and monitored in the study, those who followed a mixed vaccination scheme, with the first dose of Oxford/AstraZeneca and the second dose of Pfizer/BioNTech, generated a greater number of antibodies compared to the two doses of Oxford/AstraZeneca vaccine. The data also revealed that the levels of antibodies, after the two doses of the Pfizer/BioNTech vaccine, were higher than those generated with other vaccination schemes.

Besides following educational professionals from Oeiras Municipality, this longitudinal study also followed health professionals from the Centro Hospitalar Lisboa Ocidental EPE. Learn more about these results here. 

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