An important lesson for vaccine design
Published today in PLOS Medicine, the study was made possible by a partnership between the University of Sydney, Kids Research, Sydney Children’s Hospitals Network, the Kirby Institute at UNSW Sydney, Australian Red Cross Lifeblood, St Vincent’s Hospital and NSW Health Pathology, as well as other local and international collaborators.
The team analysed the serum of 233 individuals diagnosed with COVID-19 over 7 months and uncovered that the level of immunity over time is dependent on disease severity and the viral variant. They show that antibodies developed during the first wave had reduced effectiveness against six variants, ranging from those observed in the second wave in Australia through to three variants of concern that have driven the global pandemic in the UK, Brazil and South Africa.
How do we study the immune response?
The serum of COVID-19 infected individuals was of interest as it is the part of our blood that contains crucial information about our immune system. Analysis of the serum made it possible to create a detailed timeline of the level of ‘neutralising antibodies’ produced against COVID-19 infection, and so to see if there was long-term immunity.
Neutralising antibodies are part of our immune system’s frontline arsenal that is triggered during infection and vaccination. Their job is to shield cells that are usually the target of a pathogen (such as the SARS-CoV-2 virus which causes the COVID-19 disease) from being infected. The level of neutralising antibody response can be a defining feature of how effectively our body fights off illness.
Interestingly, a rare group of ‘super responders’ was also identified as an exception.
This group of ‘super responders’ had a stable and robust level of antibodies across all COVID-19 variants. The researchers say this group could prove useful for investigating the potential of convalescent plasma (using blood from people who have recovered to treat others) which has so far proven ineffective against severe COVID-19 illness. In addition, key donors could be looked at closely and their antibodies cloned for future therapeutic use.
Why it is important?
Co-senior author Associate Professor Fabienne Brilot of the University of Sydney and Kids Research, Sydney Children’s Hospitals Network, and her research team led the analysis branch of the study, using highly sensitive tools they developed to study the antibodies in detail.
“We can learn a great deal from these people who were infected in the first wave in Australia as they were infected with the same variant that our current vaccines are based on,” said Associate Professor Brilot.
“While the approved vaccines are showing good responses, our study highlights the importance of continued vaccine development, especially taking into account the differences in variants.”
Co-senior author Associate Professor Stuart Turville of the Kirby Institute said the study was conducted to investigate the level, breadth and longevity of the immunity generated from COVID-19 infection and whether mutation of the virus compromises immunity.
“What this work has shown us is that current observations about vaccines show they offer a much broader protection against COVID-19 and its variants than the body’s natural immune response following infection, which is usually only protective against the variant of the virus that the person was infected with. We, therefore, should not rely on the body’s natural immune response to control this pandemic, but rather the broadly protective vaccines that are available.”

News
Inhalable Nanovaccines: The Future of Needle-Free Immunization
The COVID-19 pandemic highlighted the need for adaptable and scalable vaccine technologies. While mRNA vaccines have improved disease prevention, most are delivered by intramuscular injection, which may not effectively prevent infections that begin at [...]
‘Stealthy’ lipid nanoparticles give mRNA vaccines a makeover
A new material developed at Cornell University could significantly improve the delivery and effectiveness of mRNA vaccines by replacing a commonly used ingredient that may trigger unwanted immune responses in some people. Thanks to [...]
You could be inhaling nearly 70,000 plastic particles annually, what it means for your health
Invisible plastics in the air are infiltrating our bodies and cities. Scientists reveal the urgent health dangers and outline bold solutions for a cleaner, safer future. In a recent review article published in the [...]
Experts explain how H5 avian influenza adapts to infect more animals
A new global review reveals how rapidly evolving H5 bird flu viruses are reaching new species, including dairy cattle, and stresses the urgent need for coordinated action to prevent the next pandemic. Since its [...]
3D-printed device enables precise modeling of complex human tissues in the lab
A new, easily adopted, 3D-printed device will enable scientists to create models of human tissue with even greater control and complexity. An interdisciplinary group of researchers at the University of Washington and UW Medicine [...]
Ancient DNA sheds light on evolution of relapsing fever bacteria
Researchers at the Francis Crick Institute and UCL have analyzed ancient DNA from Borrelia recurrentis, a type of bacteria that causes relapsing fever, pinpointing when it evolved to spread through lice rather than ticks, and [...]
Cold Sore Virus Linked to Alzheimer’s, Antivirals May Lower Risk
Summary: A large study suggests that symptomatic infection with herpes simplex virus 1 (HSV-1)—best known for causing cold sores—may significantly raise the risk of developing Alzheimer’s disease. Researchers found that people with HSV-1 were 80% [...]
Nanoparticle-Based Combination Therapy for Resistant Melanoma
A recent study published in Small addresses the persistent difficulty of treating refractory melanoma, an aggressive form of skin cancer that often does not respond to existing therapies. Although diagnostic tools and immunotherapies have improved in [...]
Our DNA May Evolve Much Faster Than Previously Thought
Rapidly mutating DNA regions were mapped using a multi-generational family and advanced sequencing tools. Understanding how human DNA changes over generations is crucial for estimating genetic disease risks and tracing our evolutionary history. However, some of [...]
AI therapy may help with mental health, but innovation should never outpace ethics
Mental health services around the world are stretched thinner than ever. Long wait times, barriers to accessing care and rising rates of depression and anxiety have made it harder for people to get timely help. As a result, governments and health care providers are [...]
Global life expectancy plunges as WHO warns of deepening health crisis Post-COVID
The World Health Organization (WHO) has sounded the alarm on the long-term health repercussions of the COVID-19 pandemic in its newly released World Health Statistics Report 2025. The report reveals a staggering decline in global [...]
Researchers map brain networks involved in word retrieval
How are we able to recall a word we want to say? This basic ability, called word retrieval, is often compromised in patients with brain damage. Interestingly, many patients who can name words they [...]
Melting Ice Is Changing the Color of the Ocean – Scientists Are Alarmed
Melting sea ice changes not only how much light enters the ocean, but also its color, disrupting marine photosynthesis and altering Arctic ecosystems in subtle but profound ways. As global warming causes sea ice in the [...]
Your Washing Machine Might Be Helping Antibiotic-Resistant Bacteria Spread
A new study reveals that biofilms in washing machines may contain potential pathogens and antibiotic resistance genes, posing possible risks for laundering healthcare workers’ uniforms at home. Washing healthcare uniforms at home could be [...]
Scientists Discover Hidden Cause of Alzheimer’s Hiding in Plain Sight
Researchers found the PHGDH gene directly causes Alzheimer’s and discovered a drug-like molecule, NCT-503, that may help treat the disease early by targeting the gene’s hidden function. A recent study has revealed that a gene previously [...]
How Brain Cells Talk: Inside the Complex Language of the Human Mind
Introduction The human brain contains nearly 86 billion neurons, constantly exchanging messages like an immense social media network, but neurons do not work alone – glial cells, neurotransmitters, receptors, and other molecules form a vast [...]