COVID-19 Infection Provides Temporary Immunity, Though Not From Transmission, Says Study COVID-19 Science 15/01/2021 • Raisa Santos Share this:Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Facebook (Opens in new window)Click to print (Opens in new window) COVID-19 immunity from previous infection does not guarantee people still won’t carry and transmit the virus Past COVID-19 infection may provide immunity for several months, but still leaves risk of transmission to others, a Public Health England (PHE) study has found. “This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections but there is still a risk that you could acquire an infection and transmit to others,” said Professor Susan Hopkins, Senior Medical Advisor at PHE and study lead at SARS-CoV-2 Immunity and Infection EvaluatioN (SIREN). Since June, the PHE’s SIREN study has performed regular antibody and PCR testing on 20,787 healthcare workers, including frontline clinical staff and those in non-clinical roles. 6,614 of these participants tested positive for COVID-19 antibodies upon recruitment. Between 18 June to 24 November, there were 44 potential reinfections identified by the study, with 2 designated ‘probable’ and 42 ‘possible’ based on available evidence. If all 44 cases were confirmed, this would represent an 83% rate of protection from reinfection, though if only the 2 ‘probable’ reinfections were confirmed, the rate would be 99%. Further research is ongoing to clarify this range. The study found that antibody protection after infection lasts for at least 5 months, on average. Scientists are studying whether this protection may last for longer, but this means that many people who contracted the disease in the first wave of the pandemic may now be vulnerable to reinfection. Although those with antibodies have some temporary protection against COVID-19, some of these individuals carry high levels of the virus and could continue to transmit the virus to others. More Research Needed to Understand Effectiveness of Vaccines in Reducing Transmission In December, the UK identified a vriation of SARS-CoV-2 now known as VOC 202012/01 (Variant of Concern), but formerly referred to as VUI 202012/01 (Variant Under Investigation). Further work is underway to understand whether and to what extent antibodies also provide protection from this variant. The study will continue to follow participants for 12 months to explore how long any immunity may last and to what extent people with immunity are able to carry and transmit the virus. Peer reviewed Phase 3 clinical trial results for Moderna vaccine, published 30 December 2020 in the New England Journal of Medicine, have suggested that vaccination also reduced asymptomatic transmission by about two-thirds, in the case of Moderna’s mRNA-1273 vaccine, though the numbers examined were small. The duration of immunity and the amount of the virus reduced in those vaccinated still needs to be researched. SIREN data from the first report does not provide evidence towards antibody or immune responses from COVID-19 vaccines. Vaccine effectiveness will also be studied later this year by the PHE SIREN study. With cases at their highest level to date in the United Kingdom, the PHE advocates that everyone does their part to avoid the risk of transmitting to other people. Said Hopkins: “This study has given us the clearest picture to date of the nature of antibody protection against COVID-19 but it is critical people do not misunderstand these early findings.” “Now more than ever it is vital we all stay at home to protect our health service and save lives.” Image Credits: Yuri Samilov/Flickr. Share this:Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Facebook (Opens in new window)Click to print (Opens in new window) Combat the infodemic in health information and support health policy reporting from the global South. Our growing network of journalists in Africa, Asia, Geneva and New York connect the dots between regional realities and the big global debates, with evidence-based, open access news and analysis. To make a personal or organisational contribution click here on PayPal.