Introduction: The coronavirus is an RNA virus with a lipid envelope. The initially known coronaviruses are (MERS-CoV and SARS-CoV) which caused fatal endemics in 2002 and 2012. At the end of 2019, a new variant of coronavirus called SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) was discovered in Wuhan in China. SARS-CoV-2 has caused serious diseases especially in the older groups with millions of infections and deaths. The World Health Organization (WHO) identified Covid-19 as a global health emergency on 30 January 2020 and classified it as a pandemic on March 11, 2020. Several companies started developing a vaccine to stop the spread of SARS-CoV-2. Several vaccination programs have been approved and are currently used against Covid-19. Objectives: The work aimed to investigate the safety and efficacy of the approved mRNA-based vaccines against SARS-CoV-2. Method: The work was based on reviewing published, scientific articles that examined safety and efficacy of mRNA-based vaccines (Pfizer BionTech BNT162b and mRNA-1273 Modern). In total there were five clinical trials selected from Pubmed. Two studies examined the safety and efficacy of mRNA-1273 Moderna and three other studies examined the safety and effectiveness of the Pfizer BionTech BNT162b. Results: Both vaccines have shown good safety and efficacy and were well tolerated in patients in different ages. mRNA-based vaccines have shown mild to moderate symptoms that were higher after dose 2 and disappeared after a few days. Both Pfizer BionTech and Modern mRNA-1273 have shown efficiencies over 90%.

Introduktion: Coronavirus är RNA-virus med ett lipidhölje som är täckt utav karaktäristiska spikprotein. De mest kända coronavirusvarianterna är SARS-CoV-1 som var aktiv mellan 2002-2004, MERS-CoV som har varit aktiv sedan 2012 och SARS-CoV-2 som har varit aktiv sedan 2019–tillsvidare. SARS-CoV-2 infektionen betecknades januari 30 2020 som en pandemi. Flera läkemedelsföretag har forcerat ??? till att framställa vaccin riktad mot SARS-CoV-2, “The United States Food and Drug Administration” (FDA) och “European Medicines Agency” (EMA) har nödgats att ge ut “Emergency Use Authorization (EUA) i hopp om att få kontroll på dess spridining. Syfte och mål: Syftet med arbetet är att undersöka säkerheten och effektiviteten hos de EMA-godkända vaccinerna riktade mot SARS-CoV-2. Metod: Studierna för vardera vaccin hittades och valdes ut genom World Health Organizations (WHO) “Draft landscape and tracker of COVID-19 candidate vaccines”. Totalt inkluderades åtta studier baserade på tio kliniska prövningar som undersökte säkerheten och effektiviteten hos de fyra ledande vaccinerna från Pfizer BioNTech, Moderna, AstraZeneca och Johnson & Johnson. Resultat: De fyra undersökta vaccinerna visade en god säkerhet utan grövre biverkningar. De vanligaste biverkningarna hos samtliga vaccin var lokal smärta, trötthet och huvudverk. Dessa biverkningar varade mellan en till två dagar efter vaccination och var till större del milda. Större skillnader kunde ses hos de olika vaccinernas effektivitet, Pfizer BioNTech och Modernas mRNA-vacciner visade på effektiviteter runt 95% medan AstraZeneca och Johnson & Johnsons adenovirus-vektor-vacciner visade på effektiviteter runt 66-70%. Diskussion: Inga större skillnader i säkerhet kunde ses mellan de undersökta vaccinerna. AstraZeneca använde ett influensa vaccin istället för isoton vattenlösning till deras kontrollgrupper. Detta kan ha haft en påverkan på placebo och resultaten från deras prövningar. En tydlig skillnad i effektivitet kunde ses mellan de olika vaccintyperna, vilket har ett stort inflytande på hur lätt man kan inducera flockimmunitet hos en befolkning. Eftersom flockimmunitet har en stor roll i både att bromsa spridningen men även i att förebygga förekomsten av nya virus varianter så bör endast mRNA vacciner rekomenderas om möjligt. / Introduction: Coronaviruses are RNA viruses with a lipid envelope that is covered by characteristic spike protein. The most well-known coronaviruses are SARS-CoV-1 which were active between 2002-2004, MERS-CoV which is active since 2012 and SARS-CoV-2 which is active since 2019. SARS-CoV-2 was designated a pandemic January 30, 2020. Several pharmaceutical companies have been rushing to produce vaccines targeting SARS-CoV-2, The United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have had to issue Emergency Use Authorization (EUA) in the hope of gaining control of its spread. Objective: The purpose of this study is to investigate the safety and efficacy of the EMA-approved vaccines targeting SARS-CoV-2. Method: The studies for each vaccine were found and selected through the World Health Organizations' (WHO) "Draft landscape and tracker of COVID-19 candidate vaccines". A total of eight studies were included based on ten clinical trials examining the safety and efficacy of the four leading vaccines from Pfizer BioNTech, Moderna, AstraZeneca and Johnson & Johnson. Results: The four vaccines examined showed good safety without any serious side effects, the most common side effects with all vaccines were local pain, fatigue, and headache. These side effects lasted between one to two days after vaccination and were mostly mild. Larger differences could be seen in the efficacy of the different vaccines, with Pfizer BioNTech and Moderna's mRNA vaccines showing efficacies of around 95%. While AstraZeneca and Johnson & Johnson's adenovirus vector vaccines showed efficacies of around 66-70%. Discussion: No major differences in safety could be seen between the vaccines examined. AstraZeneca used an influenza vaccine instead of isotonic aqueous solution for their control groups, this may have had an impact on placebo and thus the results of their trials. A clear difference in efficacy could be seen between the different types of vaccines. This has a great influence on how easily one could induce herd immunity to a population. Herd immunity plays a major role in both slowing the spread but also in preventing the occurrence of new virus variants, therefore mRNA vaccines should be recommended if possible.

The rapid development, approval, and production of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than 1 year after the first reports of a new infectious disease was a real game changer, providing 80%–90% efficacy in preventing severe etiopathologies of the coronavirus disease 2019 (COVID-19). These vaccines induce an immune response against the SARS-CoV-2 spike (S) protein located on the surface of the virus particle. Antibodies (Abs) recognizing the S-protein can inhibit binding of the virus via the S-protein to the angiotensin-converting enzyme-2 (ACE-2) receptor expressed on different human cells, especially when these Abs bind to the interaction site, the so-called receptor-binding domain (RBD). We have expressed the RBDs of wild-type SARS-CoV-2 and five variants of concern (VOCs) to test the immune response in people before vaccination with mRNA vaccines BNT162b2 and mRNA-1273 and after up to three vaccinations using in-house ELISA and inhibition assays. The methods of both assays are provided. Both vaccines initiated similarly high IgG titers after two vaccinations against the wild-type and even two VOC-RBDs (alpha and delta) and strongly inhibited the corresponding RBD-ACE-2 binding. The IgG titers and inhibition of ACE-2 binding were lower for beta and gamma RBDs and much lower for omicron RBD. The third vaccination after 6 months strongly increased both the IgG titers and the neutralizing effect against all variants, especially for omicron, leading to 63% ± 13% neutralization potential. Importantly, neutralization linearly increased with the IgG titers.