Researchers in Singapore have conducted a study showing that the messenger RNA- (mRNA) based coronavirus disease 2019 (COVID-19) vaccines developed by Pfizer-BioNTech and Moderna are highly effective at protecting against symptomatic and severe disease following infection with the rapidly spreading B.1.617.2 (delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
The team conducted a multi-center retrospective cohort study of vaccinated and unvaccinated individuals who had been admitted to hospital following infection with the B.1.617.2 variant of concern.
“To our knowledge, we provide the first data characterizing the impact of vaccination on virologic kinetics by the B.1.617.2 variant,” writes Barnaby Young from the National Centre for Infectious Diseases in Singapore and colleagues.
The team found that individuals fully vaccinated with either Pfizer-BioNTech’s BNT162b2 vaccine or Moderna’s mRNA-1273 product were significantly less likely to develop moderate or severe outcomes following B.1.617.2 infection than unvaccinated individuals.
Vaccination was associated with fewer symptoms, lower peak biomarkers of systemic inflammation, and better clinical outcomes. It was also associated with a more rapid decline in viral RNA load and a robust serologic response.
“Vaccination remains a key strategy for control of COVID-19 pandemic,” says Young and colleagues.
A pre-print version of the research paper isa available on the medRxiv* server, while the article undergoes peer review.
Variants of concern pose a threat to vaccination efforts
Phase 3 clinical trials of mRNA-based vaccines have demonstrated efficacies of 92% to 95% in preventing symptomatic and severe disease following SARS-CoV-2 infection.
While the mass rollout of these vaccines has reduced infection and mortality rates in many countries, the emergence of SARS-CoV-2 variants containing mutations in the viral spike protein has led to growing concerns regarding increased transmissibility and resistance to vaccine-induced immunity.
The spike protein is the main structure the virus uses to infect cells and a primary target of binding and neutralizing antibodies following natural infection or vaccination.
While variants of concern such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617.2 (delta) have all been shown to exhibit increased transmissibility, the B.1.1.7 and B.1.617.2 strains have also been associated with increased disease severity and hospitalization.
Following the emergence of B.1.617.2 in India, this variant rapidly spread to other countries and had become the most frequently sequenced lineage worldwide by the end of June 2021.
The vaccination program in Singapore
The COVID-19 vaccination program began in Singapore on December 30th, 2020. Free vaccination with either the Pfizer-BioNTech or Moderna product was made available to all Singapore residents, beginning with the elderly and those with high-risk occupations such as healthcare workers.
As of July 19th, 2021, more than 6,837,000 vaccine doses had been administered and approximately 2,792,400 individuals had been fully vaccinated.
What did the researchers do?
Young and colleagues conducted a multi-center retrospective cohort study to characterize the clinical, virologic and serologic features of vaccinated adults with breakthrough B.1.617.2 infection. The results were compared with those of unvaccinated patients who also had B.1.617.2 infection.
Participants were recruited between April 1st and June 14th, 2021, across five study sites: the National Centre for Infectious Diseases, Singapore General Hospital, National University Hospital, Changi General Hospital and Sengkang Hospital.
When liquid meets gas, a unique zone forms. Variable by nature, molecules can cross from one state to another, combining in unique ways to either desirable or unwanted ends. From heat escaping a mug [...]
A newly detected coronavirus variant is on the rise in England, with the virus believed to be an offshoot of Delta. According to a briefing from the UK Health Security Agency, released on Friday, [...]
A team of researchers has developed a new nanomechanical technique for fast, one-step, immune-affinity tests, which can quantify the immune response induced by different COVID-19 variants in serum. Their technique provides a new tool [...]
Lawrence Livermore National Laboratory (LLNL) scientists have developed a new method for 3D printing living microbes in controlled patterns, expanding the potential for using engineered bacteria to recover rare-earth metals, clean wastewater, detect uranium, [...]
Nanomedicines may offer clinicians a way to deliver precise, targeted therapy directly to tumors without damaging surrounding tissue. Yet, progress in the development of new drugs that treat cancer at the nanoparticle level has [...]
Cambridge researchers have discovered how T cells—an important component of our immune system—are able keep on killing as they hunt down and kill cancer cells, repeatedly reloading their toxic weapons. Cytotoxic T [...]
Sunday, October 3, set records for the most COVID-19 deaths in Russia on a single day. Only 29% of people in Russia are vaccinated, despite the country being the first to approve a vaccine. [...]
New research from the University of Technology Sydney (UTS) has found that pathogens that form biofilms can evolve to survive nanosilver treatment. The study is the first to demonstrate that long-term nanosilver treatment can [...]
New variants of SARS-CoV-2 are more virulent and transmissible than the original variant of the virus. Health experts associate these variants of concern (VOCs) with increased risk of hospitalization, intensive care unit (ICU) admission, [...]
Freeze-dried genetic circuits could reveal the presence of SARS-CoV-2, Ebola, MRSA, and more. Masks and testing have been key to the COVID-19 pandemic response—and now devices that combine the two may be on the [...]
Hundreds of neuroscientists built a ‘parts list’ of the motor cortex, laying groundwork to map the whole brain and better understand brain diseases. Before you read any further, bring your hand to your forehead. [...]
An international team, led by Swinburne University of Technology and Australian National University (ANU), have made a breakthrough discovery that could potentially lead to faster, more accurate molecular or virus tests, including for COVID-19. [...]
New mutations of COVID-19, such as the Delta strain, are "getting better" at transmitting through the air, a study has found. People infected with a later variant of COVID-19 put 43 to 100 times more virus into [...]
Merck will seek U.S. approval for pill as soon as possible If approved, would be 1st oral antiviral COVID-19 drug Merck shares rally, some vaccine makers fall U.S. government to buy 1.7 mln courses [...]
An antiviral surface coating technology sprayed on face masks could provide an extra layer of protection against COVID-19 and the flu. The coating developed at The University of Queensland has already proven effective in killing [...]
Key Points Monash researchers have developed a method to prepare elongated nanocrystals to deliver therapeutic drugs Elongated nanocrystals can carry a high payload of drugs to potentially increase drug targetability and also decrease dosage [...]