Scientists from the city-state’s Duke-NUS Medical School and National Centre for Infectious Diseases (NCID) have found “highly potent functional antibodies” in people who had severe acute respiratory syndrome and were vaccinated with Pfizer-BioNTech’s shots for Covid-19.
In findings published in the New England Journal of Medicine, the scientists say these antibodies “are capable of neutralising not only all known SARS-CoV-2 variants of concern but also other animal coronaviruses that have the potential to cause human infection”.
SARS-CoV-2 is the virus that causes Covid-19.
Nearly two decades before Covid-19 upended the global economy, SARS swept through Asian and other countries. Singapore recorded 238 infections during the 2003 epidemic, with 33 deaths, according to the World Health Organization.
All told, 8,096 people were diagnosed worldwide from late 2002 to mid-2003, with 774 succumbing to the disease.
Health authorities managed to curb SARS, but Covid-19 has proved a much tougher adversary. Since it came to attention in late 2019, the new coronavirus has spawned multiple mutations, or variants, that are heightening the difficulty of quelling the pandemic.
The delta Covid-19 variant first detected in India is estimated to be 10 times harder to control than the original virus. It is fueling a global resurgence in infections, prompting some authorities to reimpose lockdowns and other restrictions.
Singapore, which has fully inoculated more than 70% of its population, is counting on its high vaccination rate to allow it to “live with Covid-19” as an endemic risk.
But in multiple countries, “breakthrough” cases have been reported in people who have had the full two-shot vaccine regimen, raising fears that the current slate of available jabs may not be sufficient to truly end the crisis.
“Emerging variants of concern have already demonstrated some degree of immune evasion against the first-generation vaccines,” noted associate professor David Lye, director at the Infectious Disease Research and Training Office of the NCID.
The discovery of the antibodies in SARS patients jabbed with Pfizer “has the potential to address that problem as the world continues Covid-19 vaccination to exit the pandemic”.
The scientists said the revelation “is the first time that such cross-neutralising reactivity has been demonstrated in humans”, which boosts hopes of developing a more effective solution against different coronaviruses.
“Our study points to a novel strategy for the development of next-generation vaccines, which will not only help us control the current Covid-19 pandemic, but may also prevent or reduce the risk of future pandemics caused by related viruses,” said professor Wang Linfa from Duke-NUS.
The findings show that before being vaccinated, the SARS survivors had no or low-level Covid-neutralising antibodies.
After two Pfizer doses, all of the SARS survivors in the study showed high antibody levels against Covid-19, as well as a broad spectrum of antibodies against 10 other respiratory viruses.
The hope is that data on the Pfizer-inoculated SARS survivors could be used to develop more effective shots.
The scientists are currently conducting a study to develop a third-generation vaccine against different coronaviruses, as well as broad neutralising antibodies for therapy, and aim to recruit individuals who recovered from SARS in 2003 for trials.