1:Centro Nacional Biotecnología, CSIC, Madrid, Spain

The emergence of the COVID-19 pandemic caused a major health and economic burden to the world, with over 500 million infections and six million deaths. Within a short time the responsible viral agent, coronavirus SARS-CoV-2, spread rapidly to all continents due to an efficient transmission of the virus through the respiratory tract and the easy to infect a naïve immune population. Rapidly, the scientific community responded through the implementation of three strategies outlined by WHO to control a pandemic: quick diagnostic tests, antivirals and vaccines. A remarkable achievement was that within a year vaccination started, administering more than ten billion doses in what has become the largest vaccination program in history. Since then, more that 60% of the world's population have received at least one dose of
different COVID-19 approved vaccines. However, there is extreme inequity in the low-income countries where less than 10% of people have received the vaccines.
From the beginning of the pandemic, our group of Poxvirus and Vaccines at the National Center of Biotechnology (CNB-CSIC) has actively participated in the development of a COVID-19 vaccine. Within a short time we generated a vaccine candidate, MVA-CoV2-S, and demonstrated in three preclinical animal models (mouse, hamster and macaques) that the vaccine was highly immunogenic and effective
against SARS-CoV-2 infection. This rapid development was possible because we previously established a vaccine platform based on the highly attenuated poxvirus vector MVA (modified vaccinia virus Ankara) that we have used in the generation of vaccines against multiple pathogens (HIV, Ebola, chikungunya, zika, hepatitis C, malaria and leishmania), showing high immunogenicity and efficacy in animal models.
In retrospect, in Spain we have learned important lessons from the pandemic, like preparedness for the making of human vaccines, the need for continuous surveillance of infectious agents, repositories and centers for rapid genomic analysis of variants of concern, active collaboration between research centers and hospitals, promote engagement of national industries to manufacture human vaccines, use of BSL-3 centers to address efficacy studies in animals, and make aware the society of the benefits of vaccines in the fight against SARS-CoV-2 and prevention of deaths.
Questions like, when the pandemic will be over, consequences of long-COVID-19 in patients, duration of protective immune responses by current vaccines, newly developed vaccines against variants of concern, use of combined protocols of immunization and potential eradication of the virus are challenges being addressed.