Tag: Vaccine

The complex relationship between viruses and our immune system

Prof John TregoningVirus Appreciation Day, celebrated annually on 3 October, serves a dual purpose: to foster respect and understanding for viruses while raising awareness about their serious impacts on health. To mark the day, Professor John Tregoning from Imperial’s Department of Infectious Disease shares valuable insights into influenza viruses, highlighting their effects, the importance of vaccination, and ongoing research for universal vaccines against evolving strains in our latest blog.

Viruses have an enormous impact on human health, but they don’t only infect humans. Many viruses also infect animals, plants and even bacteria. Some viruses are quite promiscuous, infecting a wide range of animal species before passing on to humans through a process known as zoonotic transmission. One of the most problematic of these zoonotic infections is influenza virus.  

The main natural reservoir of influenza virus is wild birds, particularly ducks and geese. The virus can then transmit from these birds into domestic poultry, like chickens, and to livestock, such as pigs, before ultimately reaching people. In the past five years, a new strain of avian influenza has emerged with an ability to infect an even wider range of mammalian species. It has been detected in cattle in the US.  

Influenza, the disease caused by the virus, poses a substantial health burden. It resulted in nearly 15,000 deaths in the UK in the 2022-23 winter season. As well as death, it is a significant cause of hospitalisation and general illness – with a long tail of recovery. Additionally, influenza infection doubles the risk of heart attacks and strokes for up to a year after illness. Given these risks, getting an influenza vaccine this time of year is highly recommended. As I discovered researching my latest book Live Forever one of the simplest ways of extending your life is through vaccination. A vaccine will give you protection against the most severe forms of disease caused by the virus and protect you against subsequent illness.Vaccines train your body to recognise pathogens and fight them off. To do this, they make use of a facet of immunity called immune memory. When re-exposed to the same virus, your immune response activates faster and stronger, stopping the infection in its tracks. Several aspects of immune memory can prevent subsequent infections, but an important one are antibodies – this is a type of protein that is highly specific in what it can recognise and bind. When you are immunised with influenza vaccine, you make influenza virus specific antibodies that can stop the virus from infecting you. 

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Covid-19 vaccination in the UK: What does the future hold?

Covid-19 vaccination centre sign

Recently, the UK Government announced that offers of first and second Covid-19 vaccinations will come to an end after 30 June. Ahead of World Immunisation Week, Professor Azeem Majeed from the School of Public Health discusses this major change in national vaccine policy, and why it’s important to stay up to date with Covid-19 booster vaccinations.

The announcement from NHS England that first and second doses of Covid-19 vaccines will no longer be offered to adults after 30 June 2023 signifies a significant change in national vaccine policy. We will all remember the start of the Covid-19 vaccination programme in December 2020, the rapid rollout of vaccines by the NHS, and the enthusiasm for vaccination amongst most sections of the population. Vaccination curbed the impact of Covid-19, leading to large falls in hospital admissions and deaths, and allowing the government to end Covid-19 restrictions.

We are now though entering a new phase in which Covid-19 vaccination will be restricted to older people and those in medical problems that place them at higher risk of adverse outcomes such as hospitalisation and death. The very highest risk groups – such as the immunocompromised and people aged 75 years and over – have been offered booster vaccines every six months for the past two years. Other population groups – such as NHS staff, those aged 50 and over, and people with significant medical problems – have been offered annual booster vaccines.

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Is an H5N1 ‘bird flu’ pandemic inevitable?

The largest ever outbreak of bird flu is spilling over into mammals, including foxes and otters in the UK. Could this transmission see a jump to humans? Dr Thomas Peacock from the Department of Infectious Disease discusses.

Avian influenza virus has been featured prominently in the news again over the past few months. Headlines urge vaccine stockpiling, show images of beaches covered in dead sea birds or seals, or people in hazmat suits carrying bin bags full of dead birds or mink. Three years into the COVID-19 pandemic, is another pandemic unavoidable?

We have been in this situation before, back in the late 1990s and early 2000s, headlines spoke of ‘bird flu’ – H5N1 viruses ancestral to the ones currently circulating in Europe – as the inevitable coming pandemic. In fact, in 2009 an influenza pandemic did occur, but rather than the deadly H5N1 bird flu, it was caused by an obscure swine influenza virus that passed onto humans and caused the 2009 ‘swine flu’ pandemic.

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Can we save lives by deliberately infecting people?

A person's arm being injected

In the middle of the pandemic, scientists intentionally infected healthy volunteers with SARS-CoV-2, the virus that causes COVID-19. John Tregoning, Reader in Respiratory Infections at the Department of Infectious Disease, explains why these experiments, and the volunteers who take part in them, are critical to modern medicine.

In early March 2021, in the middle of the COVID-19 pandemic, a surprising-sounding set of experiments were taking place. Researchers at Imperial College London (and separately at the University of Oxford) were deliberately infecting healthy volunteers with SARS-CoV-2. This was in fact the latest in a long line of controlled human infection studies – where volunteers are deliberately infected with an infectious pathogen under extremely controlled conditions.

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How can we manufacture the safest possible challenge agents for human infection studies?

Pipettes in a scientific lab
Dr Emma Smith—HIC-Vac Network Manager—explains how specific guidelines for the provenance and manufacture of challenge agents could make human infection studies even safer.

Human infection studies, also known as human challenge studies, are clinical trials where volunteers are intentionally given a carefully considered dose of a pathogen—known as the challenge agent. These models can be used to study host-pathogen interactions and disease progression; identify and test the efficacy of promising vaccines and drugs in development; or be used as proof-of-concept studies for testing novel medications. In this controlled environment it is possible to study infections in ways that aren’t possible in traditional field studies.

One of the first steps towards establishing a challenge study is the selection, isolation, development and production of the challenge agent. However, unlike medicines, the regulation of challenge agent manufacture varies internationally; an area that the research community has identified as a potential weakness in the field. Although human challenge studies have an excellent safety record—a recent literature review identified just 24 Serious Adverse Events (SAE) and zero deaths or cases of permanent damage among 15,046 participants in 308 studies spanning 1980 to 2021— the lack of specific guidelines for the provenance and manufacture of challenge agents warrants attention.

HIC-Vac—an Imperial-led international network of researchers who are developing human infection challenge studies—has been working with the global charitable foundation Wellcome and the company hVIVO to address this unmet need. Our purpose was to promote volunteer safety whilst maximizing access to challenge agents and challenge models globally. (more…)

COVID-19 vaccine diaries: part two, safety first

Justine is a participant in Imperial’s COVID-19 vaccine clinical trial – here she discusses how the trial is progressing. 

“Am I immune?” “Could I be immune?”

These are questions that have been unavoidably circling in my head ever since I received an experimental coronavirus vaccine as part of a clinical trial led by Imperial College London. 

Every time I exercise, take public transport, do my weekly food shop, socialise with those close to me, I’ve been trying to quash this invisible shield that part of my brain believes might be there, shrugging off any potential encounters with the SARS-CoV-2 virus. 

I didn’t enter this trial so that I’d get a free pass to behave irresponsibly in the midst of a pandemic, which is frighteningly rearing its ugly head again in my home country. I always knew that immunity was never a certainty, having never been tested in human beings before. I was more confident that it wasn’t a dangerous thing for me to do, and certain that it was a good thing to do. 

And by participating, I have certainly helped to prove both of these latter points. I’ve had two shots of the vaccine, which works by instructing my cells to make fragments of the coronavirus, thereby prompting my immune system to react and, hopefully, keep a protective memory of the threat. I’ve had no side effects at all; not even a sore arm. The devil on my shoulder sort of wished for even a little redness where the needle went in, that I could wear proudly as a mark of my contribution to research.  (more…)

COVID-19 vaccine diaries: part one, my first dose

Justine is taking part in Imperial’s COVID-19 vaccine clinical trial – here she shares her experience of receiving the first dose.

It’s a strange feeling that as I write this, the cells in my arm are reading a message that scientists planted there just hours ago. 

That message – a strip of genetic code – contains the recipe for making part of the virus that causes COVID-19, SARS-CoV-2. This is the ‘spike’ protein that the virus uses to lock on to cells and invade them. The hope is that by telling my cells to churn out this molecule, my immune system will launch an effective and lasting response that could make me immune to the coronavirus. 

That’s the theory, anyway; we won’t know whether this experimental vaccine works until scientists have carried out rigorous clinical studies and gathered enough data to be confident of how safe and effective it is. And today I was part of that clinical research. 

I’m one of 120 people who have so far been selected to take part in one of the earliest phases of a clinical trial that’s testing Imperial’s newly-developed coronavirus vaccine. As soon as I spotted that the trial was recruiting participants, I immediately slotted my details into the online form to express my interest in joining, and eagerly awaited a response. (more…)

How reconstructing the past hepatitis B epidemic can help prevent liver cancer in the future

Nora Schmit was shortlisted for the MRC Max Perutz Science Writing Award 2019 for the following article on her PhD research on predicting the impact of treatment for hepatitis B infection on preventing liver cancer in The Gambia.

What’s the first thing that comes to your mind when you think of cancer prevention? Maybe you’re thinking of not smoking or maintaining a healthy weight – great strategies to reduce your chance of getting cancer.

But did you know that the hepatitis B vaccine, introduced in the 1980s, has long protected children in many parts of the world from developing one of the most common and deadliest cancers later in life?

Although most people have no symptoms when they first become infected, the hepatitis B virus is the leading cause of liver cancer worldwide. Large-scale efforts to tackle the virus using vaccination have been hugely successful in preventing infections in children. Despite this remarkable achievement, hepatitis B infections are still very common and nearly a million people die from its consequences every year. With around 6% of all people living in Africa currently infected, the death toll there is expected to rise even further.

But while a liver cancer diagnosis is nearly always fatal, treating the infection is possible with the same drugs that work against HIV. So why do so few people receive these drugs, when over half of all liver cancer deaths globally are preventable? (more…)

The mystery of the typhoid toxin

Typhoid toxin

Dr Malick Gibani unravels the mystery behind the role of typhoid toxin in causing typhoid fever  – a disease that affects around 11 million people each year globally.

Salmonella Typhi is a fascinatingly complex bacterium. Whilst there are more than 2000 different (sero)types of Salmonella, there’s something special about Salmonella Typhi that sets it apart from the non-typhoidal Salmonella serovars. It causes different symptoms, the means of spread are different and the host it infects is different – specifically, Salmonella Typhi only causes disease in humans.

Understanding the mechanisms of how bacteria can cause disease is profoundly important for vaccine development. The Vi-antigen that forms the major component of injectable typhoid vaccines seems to have a key role in making the bacteria more virulent (hence the name). Vi-based vaccines have proven to be highly effective tools to prevent typhoid. (more…)

Outpacing outbreaks: how we’re making cheaper vaccines, faster

Dr Cleo Kontoravdi and Dr Zoltán Kis

When outbreaks emerge, speeding up vaccine development could be the difference between life and death. In this post, Dr Zoltán Kis provides an insight into how Imperial’s chemical engineers are making speedy vaccines a reality.

The worst Ebola epidemic in history swept across West Africa between 2014 to 2016, claiming 11,300 lives. This major outbreak was closely followed by the 2015-2016 Zika epidemic in Latin America. Preventing future epidemics is more important than ever and developing new vaccines are an essential weapon in fighting disease outbreaks. However, with the average vaccine development lasting 10 years, this is not comparable to the speed and frequency of outbreaks which can cause calamity in a matter of months. (more…)