Why immune responses to vaccines vary from person to person

Study finds past immune encounters may predict future vaccine response

Arizona State University

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Pre-existing antibody patterns may reveal how strongly a person will respond to vaccination, helping identify individuals at risk of a blunted immune response.

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Credit: Graphic by Jason Drees for the Biodesign Institute At Arizona State University

Vaccines protect most people from serious illness, but the strength of that protection can vary considerably from one person to another. A new study led by Arizona State University helps us understand why.

Before a vaccine ever enters your body, your immune system may already hold clues to how strongly it will respond. In blood samples from more than 4,000 people, ASU researchers and their colleagues measured antibodies against 185 antigens—targets recognized by the immune system, including those from common viruses and bacteria as well as targets associated with autoimmune diseases.

They then used artificial intelligence to analyze patterns in samples collected before and after COVID-19 vaccination, identifying antibody signatures that helped distinguish strong vaccine responders from weak ones.

The research opens a possible path toward more personalized vaccination strategies.

“What our study found is that certain biomarkers, when analyzed with AI, can predict who is likely to respond well to a vaccine, even before they receive it. This suggests that some people may be more immune-ready than others,” says Joshua LaBaer, who led the study.

LaBaer is the executive director of the Biodesign Institute at ASU and director of the Virginia G. Piper Center for Personalized Diagnostics. The research was conducted with ASU colleagues and collaborators from medical and research institutions across the country.

The study appears in the current issue of the journal Cell Press Blue. 

Antibody clues reveal immune readiness

Usually, scientists evaluate vaccine response after the shot, by measuring whether the immune system produced antibodies against the target. Here, the researchers asked a different question: Could patterns already present in the blood predict the response before vaccination?

Age, sex, genetics, prior illnesses and underlying health conditions have all been linked to how strongly people respond to vaccines. People with immune-compromising conditions are often at higher risk of weaker responses. But even within these groups, outcomes can differ sharply.

The new approach is one of the first to use a broad, pre-vaccine antibody “fingerprint” to assess immune readiness. Unlike some prediction methods that rely on genetic analyses, this strategy uses antibody patterns in blood, which may be easier to adapt for clinical use.

Beyond immune categories

To test whether that antibody fingerprint could reveal vaccine readiness, the researchers analyzed antibody responses to 185 antigens. These included SARS-CoV-2, the virus that causes COVID-19, other common viruses and bacteria, and targets associated with autoimmune diseases.

The study included 8,687 samples from 4,089 participants, spanning healthy volunteers and people with conditions or treatments linked to immune suppression, such as HIV, multiple myeloma, solid organ malignancy, autoimmune disease, inflammatory bowel disease and solid organ transplantation.

The researchers found that several immunosuppressed groups were more likely to have blunted responses to COVID-19 vaccination. But those categories were imperfect predictors. Some immunosuppressed participants mounted strong responses, while about 5% to 6% of healthy participants had weak responses.

Sentinel antibodies

The study found that higher levels of certain preexisting antibodies, including antibodies to common microbes such as Staphylococcus aureus, RSV and human respirovirus 3, were associated with stronger COVID-19 vaccine responses.

The researchers describe these as “sentinel” antibodies because they may indicate a person’s baseline immune readiness. They are not necessarily fighting the vaccine target directly. Instead, they may reflect how responsive the antibody-producing arm of the immune system is likely to be.

The researchers then asked whether the full antibody fingerprint, not just a few individual markers, could help identify people likely to have weak vaccine responses. Their deep-learning model analyzed patterns across the antibody panel, combining many measurements into a broader immune profile.

The study highlights a key strength of AI in health research: its ability to find subtle, predictive patterns in millions of biological data points that might otherwise remain hidden. The approach suggests that vaccine readiness may be better understood by looking at the immune system as a whole, rather than focusing only on a single disease or a single antibody.

The work also highlights the value of newer technologies that can measure large numbers of antibody responses at once. Instead of asking whether someone has antibodies to one pathogen, the method can scan a wider immune landscape, capturing patterns formed by many previous encounters with viruses, bacteria and other immune targets.

The researchers say the findings could have implications beyond COVID-19, if they are validated in additional studies and with other vaccines. Sentinel antibody profiling could help guide vaccine testing, vaccine development and clinical care for people at risk of weak immune responses.

The approach might eventually help doctors identify patients who need additional vaccine doses, closer follow-up or alternative protective measures. It could also help researchers better understand why some people respond well to vaccination while others do not.

The work points toward a future in which vaccine decisions could be guided by a person’s own immune readiness.

 

 

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Journal

Cell Press Blue

DOI

10.1016/j.cpblue.2026.100088 

Method of Research

Observational study

Subject of Research

People

Article Title

Pre-vaccine sentinel antibodies predict blunted vaccine responses

Article Publication Date

20-Aug-2026

 

Welcome to the jungle: newly-discovered snake named after Slash from Guns N’ Roses

Field Museum

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Slash and Sara Ruane, the paper's senior author, at the Field Museum, with Sara's copy of Reptiles Magazine featuring Slash on the cover.

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Credit: Courtesy of Sara Ruane

Slash, aka Saul Hudson, is probably best known as the guitarist from Guns N’ Roses. But there’s more to Slash than his music. He’s also a lifelong reptile lover and an avid supporter of zoos and museums. And now, he’s the namesake of the newly-discovered Lielaphis slashi: Slash’s groundsnake.

“As a long time herpephile, I am extremely honored and humbled to have Lielaphis slashi from New Guinea named after me. It is really exciting, I never would have imagined this moment would arrive,” says Slash.

“Guns N’ Roses has been one of my favorite bands since I was in first grade, and by fifth grade, I had already told my teacher that I wanted to be a herpetologist-- a scientist who studies reptiles-- when I grew up,” says Sara Ruane, the Field Museum’s Associate Curator of Herpetology and senior author of a paper in Zootaxa describing the new species. “So when I was twelve years old and got my copy of Reptiles Magazine in the mail and it had a picture of Slash holding his pet reticulated python on the cover, I thought, ‘This guy is so cool.’”

When she grew up to be a scientist who occasionally gets to give new reptile species official scientific names, Ruane thought back to the magazine article. “I reread his interview, and he talked about how much he loves museums and zoos and natural history, and about how when he was a kid, he’d go outside and look for snakes-- it was all stuff that I really related to, and it made me think that he’d be a great person to name a new species after,” says Ruane.

Ruane finally got her chance with a 28-inch-long reddish-brown snake from the forests of New Guinea.

New Guinea is the second-largest island in the world, after Greenland. It’s located just north of Australia, and the landmass is divided between the countries of Indonesia and Papua New Guinea. The island’s dense tropical forests contain untold biodiversity, but it hasn’t been well-studied by scientists. One night in 2006, Chris Austin, a professor and curator of herpetology at the Louisiana State University Museum of Natural Science, was conducting fieldwork in New Guinea when he came across an unfamiliar snake.

 “These New Guinea groundsnakes are nocturnal, so the best way to find them is at night. They are typically found just after sunset at the base of large trees where they are looking for something to eat,” says Austin, a co-author of the paper describing the new species. “When working at night in New Guinea you need to be very careful as there are several highly venomous species that look very similar to the non-venomous groundsnakes.”

In 2016, after finishing her doctorate, Ruane spent time working with Austin at LSU and the two of them teamed up to start better studying the poorly known snakes of New Guinea and have been collaborating ever since on the topic.

Based on the snake’s appearance alone, it wasn’t clear that it belonged to a new species. But back in the laboratory, analyses made it clear that this was something different. "Using multiple cutting-edge genetic analyses, we found that L. slashi is genetically distinct from other similar snakes in the same genus,” says Tianqi Huang, the study’s first author and a post-doctoral researcher at the Field Museum with Ruane. "The combination of physical characteristics, like differences in numbers of scales when compared with other species, and the genetic evidence is what led us to realize that it is an entirely new species. We also used ecological modeling to show that L. slashi's preferred habitat is different from similar snakes.”

There is still a lot to be learned about Slash’s groundsnake. “It’s incredibly hard to observe snakes in the wild before they slither away, so our knowledge about L. slashi is limited,” says Ruane. But features of the snake’s anatomy give some clues. “Snakes in this genus often have large teeth in the back of their mouths, which New Guinea groundsnakes may use to grab on to and eat small, slippery-scaled lizards and the eggs of other reptiles; this snake isn't grasping and squeezing its prey like a boa constrictor,” says Ruane. While Guns N’ Roses has been called the “most dangerous band in the world,” L. slashi does not produce any venom that could seriously harm a person.

While Slash’s groundsnake doesn’t pose a threat to humans, human activity could spell disaster for this snake and its fellow forest-dwelling creatures in New Guinea.

“The habitats that Slash’s groundsnake is from are under threat from industries like coffee farming and mining,” says Ruane. “That’s part of why describing the species that live there is important. Every species should be recognized in order for us to better understand how ecosystems work, how everything fits into the environment. We can't conserve animals or other living things that we don't know about.”

This study was contributed to by Tianqi Huang (Field Museum and Rutgers University), Chris Austin (Louisiana State University Museum of Natural Science), Justin Bernstein (Slippery Rock University and the American Museum of Natural History), Bulisa Iova (Papua New Guinea National Museum and Art Gallery), Jackson Roberts (Virginia Museum of Natural History), Jeffrey Frederick (University of Kentucky), and Sara Ruane (Field Museum).

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The new species of snake, L. slashi.

Credit

Chris Austin

Professor Chris Austin with colleagues Jim Anamiato (standing) and Ilaiah Bigilale from the Papua New Guinea National Museum and Art Gallery, Sandaun Province Papua New Guinea in 20026.

Credit

Credit: Courtesy of Chris Austin.

Journal

Zootaxa

DOI

10.11646/zootaxa.5866.2.6 

Article Title

A new species of Papuan groundsnake (Squamata: Colubridae: Lielaphis) from New Guinea

Article Publication Date

11-Aug-2026

 

World Mosquito Day 2026: European Union scientists highlight essential role of mosquito control to tackle increase in mosquito-borne diseases in Europe

Continued research on interventions and cross-sectoral collaboration needed to develop effective mosquito control strategies

European Centre for Disease Prevention and Control (ECDC)

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Mosquito control is crucial to address the increase in mosquito-borne diseases in Europe such as dengue, chikungunya virus disease, and West Nile virus infection, according to EU scientists from the European Centre for Disease Prevention and Control (ECDC), the European Chemicals Agency (ECHA), the European Environmental Agency (EEA), and the European Commission, in an article published in Eurosurveillance.

The article was published on World Mosquito Day 2026. This day, observed annually on 20 August, raises awareness about the dangers of mosquito-borne diseases. Global warming, changing environmental conditions, and more frequent international travel, have led to an increase in transmission and outbreaks of mosquito-borne diseases in Europe and worldwide.

According to the authors, mosquito control efforts are challenged by fragmented governance, limited data on cost-effectiveness and safety of available measures, and a narrow range of approved biocidal substances which are threatened by increasing mosquito resistance to insecticides. Briet et al., recommend continued investment in research to address these issues in order to develop sustainable, evidence-based and integrated mosquito control strategies.

Moreover, the authors emphasise that Europe should promote a One Health approach, which brings together the public health, environmental, veterinary and urban planning sectors to improve the effectiveness of interventions.

Control measures are available, but considerable uncertainties remain

Several methods to curb mosquito populations exist. Stagnant water, where mosquito larvae grow, can either be removed or treated with larvicides. During outbreaks, adult mosquitoes can be controlled with biocides. The sterile insect technique (SIT), which is currently being piloted in Europe, involves releasing sterilised male mosquitoes that mate with females and result in infertile eggs.

Additionally, personal protective measures to prevent mosquito bites can help with efforts to control mosquitoes and mosquito-borne diseases. These include using repellents, physical barriers, such as nets, window and door screens, and protective clothing.

However, several challenges remain. There are still uncertainties about the cost effectiveness of these methods, and interventions need to be adapted to local conditions. There are also differences across countries regarding which biocidal products are available or how they can be used.

Pyrethroids, which comprise the majority of approved substances for use in biocidal products, are effective tools for adult mosquito control, but concerns remain about environmental and human health impacts from their wider use. Furthermore, mosquito resistance against these insecticides is increasing.

Mosquito-borne diseases are not always seen as a political priority, which can be limit investment in their surveillance and control.

Cooperation across sectors essential for effective mosquito control

Mosquito control in European countries and at the EU level is overseen by a diverse set of authorities and institutions. In countries, it is usually the responsibility of Ministries of Health, though this is sometimes delegated to municipal authorities. Other ministries are also often involved. Control plans are typically made sub-nationally and deployed by private contractors. In ECDC surveys from 2020 and 2025, 20 out of 29 countries reported having active control measures, with most efforts targeting mosquito larvae. Additionally, the general population also plays a role through personal protective measures.

Action at the EU level involves several institutions with complementary mandates, collaborating both formally and informally through shared science, funding and coordination mechanisms.

ECDC and the European Food Safety Authority (EFSA) provide scientific guidance on public and animal health, respectively, as well as surveillance. ECHA evaluates biocidal substances for mosquito control, while the EEA provides environmental and climate data that help assess risk. Meanwhile, the European Commission oversees the implementation of EU health legislation and supports public health measures, vector surveillance and control through several initiatives and funding.

Together, these activities contribute to a stronger and more coherent approach to addressing vector borne disease risks across Europe.

Given the current complexities in control measures and governance, Briet et al. recommend sustainable, evidence-based and integrated mosquito control, implemented across subnational, national and EU levels. These activities should be embedded in a cross-sectoral One Health approach to reduce outbreak risk while protecting public health, animal health and ecosystems.

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Journal

Eurosurveillance

DOI

10.2807/1560-7917.ES.2026.31.33.2600306 

Method of Research

Commentary/editorial

Subject of Research

Not applicable

Article Title

Strengthening mosquito control to manage emerging mosquito-borne diseases

Article Publication Date

20-Aug-2026

Mussels get scared too

There is good reason to clam up when parasites come calling. New research shows how the “ecology of fear” can dramatically change the behaviour of blue mussels – with potential consequences that reach far beyond the individual mussel

Aarhus University

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Pernille Kibak in her Aarhus University laboratory, sorting mussels for the parasite experiments she is currently conducting. The mussels are placed in different aquaria depending on the experimental setup.

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Credit: Karolin Janina Demtröder

For a blue mussel, a good meal does not come entirely without risk.

Blue mussels feed by filtering microscopic algae from seawater. But some unwelcome guests can slip in along with their food. Tiny parasite larvae can hitch a ride as the mussel pumps water in and out.

New research from Aarhus University shows that blue mussels have a defence. When they detect the risk posed by certain parasites, they simply reduce their filtration. And when things get particularly risky, they can even close their shells completely.

This leaves the mussel with something of a dilemma: if it stops filtering, it stops eating. But there is more at stake than the mussel’s own dinner. A single large blue mussel can filter up to 100 litres of seawater a day, and millions of mussels can congregate in large beds.

Here, they act as ecosystem engineers. By filtering microalgae from the water, mussels affect water clarity and nutrient cycling. The beds themselves also form a landscape of shells, gaps and crevices that provide habitats for small animals, fish and plants. So when fear of parasites causes mussels to cut back on one of their most important activities, the effects could potentially be felt on a much larger scale.

“That is what makes this response so interesting. We are looking at something that happens in an individual mussel, but because blue mussels play such an important role in coastal ecosystems, even small changes in their behaviour could potentially matter on a much larger scale,” says PhD student Pernille Kibak, one of the researchers behind the study, which has just been published in the scientific journal Journal of Helminthology.

Fear changes mussel behaviour

The researchers explored the phenomenon in a series of laboratory experiments in which they exposed blue mussels to larvae from three different species of parasitic flatworm.

Two of the species can infect blue mussels, while the third infects fish and therefore does not pose the same threat. The clearest response occurred with the parasite Himasthla elongata. In its presence, the mussels reduced their filtration activity by 34 per cent. When the researchers combined H. elongata with another mussel parasite, Renicola roscovita, filtration fell by 51 per cent compared with the control group.

The researchers also found a clear link between filtration activity and the parasites’ success. The more actively a mussel filtered, the more parasites were subsequently found inside it. By reducing filtration, the mussel can therefore make it harder for parasites to get in.

“But what is particularly interesting is that the mussel responds to the risk before the parasite has had a chance to cause harm. It changes its behaviour simply because of the prospect of infection. That is exactly the mechanism we are talking about when we use the term ‘ecology of fear’,” says Pernille Kibak.

The concept originally comes from research into predators and prey. Predators do not shape their surroundings only by eating other animals. The mere risk of becoming someone else’s dinner can cause prey to change their behaviour, move to different areas, or spend more time keeping watch and less time feeding.

Researchers have since extended the idea to parasites. Although a parasite does not necessarily kill its host in the same way a predator kills its prey, infection can impair growth, survival and reproduction. Detecting danger early can therefore pay off.

The researchers also wanted to find out whether blue mussels can actually distinguish between parasites that can infect them and those that cannot. Here, the results were less clear-cut. The mussels responded differently to the three species, but variation between individual mussels was too great for the researchers to conclude that blue mussels can distinguish between the different parasite species.

Something in the water

The next experiment brought a surprise.

The researchers removed the parasites themselves and instead exposed the blue mussels to water containing chemical cues from common periwinkles. The snails pose no threat to blue mussels in themselves. But they play an important role in the parasites’ life cycles, because several of the parasites that later infect blue mussels first live and reproduce inside the snails.

The mussels nevertheless responded strongly. Chemical cues from the periwinkles alone caused their filtration activity to fall by almost 42 per cent compared with the control group.

“That was one of the things that surprised us most. The snail itself does not harm the mussel, but its presence can be a sign that parasites are nearby. It may almost work like a warning sign in the water: there is reason to be on your guard,” explains Pernille Kibak.

Blue mussels have a well-developed sensory system capable of detecting chemicals dissolved in the surrounding water. Food, predators, injured members of their own species and parasites can all alter the chemical composition of the water around them, providing signals to which the mussels can respond.

The researchers do not yet know exactly which signal causes the blue mussels to reduce their filtration. Water containing chemical cues from both parasites and infected snails did not cause significantly lower filtration than water containing cues from the snails alone. The results therefore suggest that cues from the periwinkle play an important role, but the precise chemical mechanism remains unknown.

That makes the finding all the more intriguing. A blue mussel spends most of its life anchored in place by strong byssal threads. It cannot simply flee when parasites appear. Instead, it has to respond to the information drifting past in the water.

When an entire mussel bed clams up

This creates a larger paradox: a response that may protect an individual mussel from parasites could potentially have consequences for the surrounding ecosystem if many mussels respond in the same way.

Mussel filtration helps move organic matter from the water towards the seabed and contributes to nutrient cycling in coastal ecosystems. The researchers therefore point out that reduced filtration could potentially affect the deposition of organic matter, nutrient cycling and the flow of energy through these ecosystems.

But there is a considerable leap from one mussel in a laboratory experiment to millions living in a natural mussel bed. Parasite abundance and environmental conditions vary in the wild, and mussels may be able to compensate for periods of reduced filtration by filtering more at other times.

“The laboratory experiments show some really interesting trends, but we cannot simply transfer them directly to a natural mussel bed. That is why it would be really interesting to study filtration activity in the field and see whether we find the same pattern under natural conditions,” says Pernille Kibak.

The question may become even more pressing as the oceans warm. Parasites pass through several life stages that are strongly dependent on temperature. Climate change could therefore alter both where parasites occur and when they are present in the water. At the same time, temperature affects the blue mussels’ own filtration activity and physiology.

“Parasites are often overlooked when we study mussel behaviour and ecology. But if we want to predict how mussels will respond to a changing climate, we also need to understand the direct and indirect effects of parasites,” she says.

The researchers are already pursuing that question. Among other things, they are studying mussels from areas where parasites are currently rare or entirely absent because temperatures are too low. If a warmer climate allows parasites to establish themselves and spread into these areas, the mussels may suddenly encounter a threat they have never faced before.

“The interesting question is whether those mussels will respond differently because they have not previously been exposed to parasites. That could give us a better understanding of how changes in parasite occurrence may affect mussel behaviour and ecology in the climate of the future,” Pernille Kibak concludes.

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Journal

Journal of Helminthology

DOI

10.1017/S0022149X26101643 

Article Title

Avoidance of parasites by blue mussels Mytilus edulis: effect of parasite species and chemosensory cues

 

Parasites leave their mark. This close-up shows blue mussel tissue under a microscope. The small pale circles are cysts formed by parasites. Parasite larvae can enter a mussel in the same stream of water it uses to filter food from the sea. This creates a dilemma: the more actively the mussel filters, the greater the potential risk of letting unwanted guests in.

The tiny white dots surrounding the common periwinkles are parasite larvae released by the snails. Periwinkles serve as hosts for several parasites that can later infect blue mussels. Surprisingly, the experiments showed that even chemical cues from the snails could cause blue mussels to substantially reduce their filtration.

Credit

Pernille Kibak