By Dr Desy Nuryunarsih on behalf of the SIREN Scotland Research Team*
The rapid speed and dissemination of information circulated online nowadays has led to numerous forms of conflicting and confusing information about world affairs. One aspect of this has been a fake news epidemic circulating around Covid-19 immunity and vaccine effectiveness. Health misinformation can pose threats to public health almost as serious as the virus itself. People who believe misinformation are prone to making poor judgements and decision making . Thus, in order to eradicate misinformation, presented here are some of the findings from the SIREN study in the hope that people can learn and be more critical about health information on the internet.
The SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) study is a large national, multicentre longitudinal cohort of around 44,294 healthcare workers across the UK’s National Health service (NHS) .The overall aim of this study is to determine if prior SARS-CoV-2 infection or COVID-19 vaccination in healthcare workers protects against future infection. . The results of the SIREN study have been published in several prestigious scientific journals and have contributed to knowledge and understanding of the protection offered by vaccines, as well as providing insights into COVID-19 reinfections [2-8]
Here we address some of the fake news encountered on social media based on SIREN findings.
1. The effectiveness of the Pfizer vaccine is not 95% but 12%, which has decreased to less than 1% based on the latest documentation published by Pfizer.
Answer from SIREN Study:
In previously uninfected participants who have received two doses of the BNT162b2 (Pfizer) vaccine, the adjusted vaccine effectiveness within 14 to 73 days after the second dose was 85%. The protection provided reached its peak in the first 2 months and waned to 51% after 6 months 
Unvaccinated participants who have been infected by SARS-COV2 had 81-89% lower risk of infection for a year after primary infection compared to participants who were previously uninfected. This protection waned after 1 year of infection, but remained high in participants with subsequent vaccination 
2. Don’t get a vaccine because it will not be effective against new SARS-CoV-2 variants
Answer from SIREN Study:
Study estimated impact of vaccines on patients facing hospital healthcare workers showed that the rapid SARS-CoV-2 vaccine rollout from December 2020 averted infection in a large proportion of hospital healthcare workers in England, without vaccine, second wave infections could have been 69% higher .
3. Natural antibody is stronger than antibody from vaccination
Answer from SIREN Study:
Infection-acquired immunity waned after 1 year in unvaccinated participants but remained consistently higher than 90% in those who were subsequently vaccinated, even in persons infected more than 18 months previously .
Unvaccinated participants who have been infected by SARS-COV2 had 81-89% lower risk of infection for a year after primary infection compared to participants who were previously uninfected. This protection waned after 1 year of infection, but remained high in participants with subsequent vaccination .
Individuals that have immunity gained from infection which is then boosted by vaccination have higher protection against the disease even more than one year after infection .
*The Scottish SIREN Team past and present: Desmond Areghan, Jennifer Bishop, Melanie Dembinsky, Laura Dobbie, Josie Evans, Lynne Haahr, Annelysse Jorgenson, Ayodeji Matuluko, Desy Nuryunarsih, Alexander Olaoye, Caitlin Plank, Lesley Price, Nicole Sergenson, Sally Stewart, Andrew Telfer, and Jenifer Weir.
- Ecker, U.K.H., et al., The psychological drivers of misinformation belief and its resistance to correction. Nature Reviews Psychology, 2022. 1(1): p. 13-29.
- Pople, D., et al., Burden of SARS-CoV-2 infection in healthcare workers during second wave in England and impact of vaccines: prospective multicentre cohort study (SIREN) and mathematical model. BMJ, 2022. 378: p. e070379.
- Wallace, S., et al., Impact of prior SARS-CoV-2 infection and COVID-19 vaccination on the subsequent incidence of COVID-19: a multicentre prospective cohort study among UK healthcare workers – the SIREN (Sarscov2 Immunity & REinfection EvaluatioN) study protocol. BMJ Open, 2022. 12(6): p. e054336.
- Atti, A., et al., Serological profile of first SARS-CoV-2 reinfection cases detected within the SIREN study. J Infect, 2022. 84(2): p. 248-288.
- Hall, V.J., et al., SARS-CoV-2 infection rates of antibody-positive compared with antibody-negative health-care workers in England: a large, multicentre, prospective cohort study (SIREN). Lancet, 2021. 397(10283): p. 1459-1469.
- Hall, V.J., et al., COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. The Lancet, 2021. 397(10286): p. 1725-1735.
- Atti, A., et al., Antibody correlates of protection from SARS-CoV-2 reinfection prior to vaccination: A nested case-control within the SIREN study. Journal of Infection, 2022.
- Hall, V., et al., Protection against SARS-CoV-2 after Covid-19 Vaccination and Previous Infection. New England Journal of Medicine, 2022. 386(13): p. 1207-1220.