What CMV means to me
For this year’s CMV Awareness month we have talked to a range of people who have all been involved with CMV in many different ways including academics, medical professionals and parents with CMV affected children. We asked them all the same question – to tell us what CMV means to them. See below for their fascinating insights including a review on the long journey to a vaccine from our Patron Professor Paul Griffiths, Emeritus Professor of Virology at University College, London.
Cytomegalovirus had been a concern to our service for many decades. In paediatrics we see the spectrum of challenges caused by congenital CMV (CMV infection of the fetus during pregnancy) that children need support with. The biggest sequelae from congenital CMV is hearing loss even in babies who seem entirely well at birth.
When research papers started to document the potential benefit of early antiviral treatment on the progression of hearing loss, the health care community were very interested and the researchers were invited to Cambridge to explain their findings. As a result, the 3 main hospitals across the East of England (Norfolk and Norwich, Peterborough and Cambridge University Hospitals) set up early screening for CMV using very simple saliva swabs of babies where even small concerns were identified on their newborn hearing the screen. This allowed the team to move faster with other investigations to look for a cause of the hearing loss, and it also allowed for early consideration of treatment with our virology colleagues or paediatric infectious disease units.
The Cambridge newborn hearing screeners are worth highlighting here. They are an extraordinary group of dedicated healthcare staff who go above and beyond every day to test each baby as early as possible after birth and to swab the saliva of any baby with any suspicion of a loss. They have been a crucial part of the team, helping to produce and disseminate education materials about CMV across the wider team and interacting with parents to inform and address questions or concerns. The hearing screeners never received any extra pay or time to take on the additional work. However babies have been identified early, and those who are positive are rapidly referred to a paediatrician to assess them medically for any other CMV signs or symptoms that can help inform decisions about treatment. Even understanding which babies are CMV negative is very helpful, since the team can progress on to other investigations such as genetics or more specialist investigations earlier which has helped children needing earlier treatment for other causes of hearing loss.
CMV action have supported our patients and the healthcare team to continue investigating children early and to help deliver health education about CMV prevention and management.
It has been one of the most incredible journeys working in the NHS to watch the area of CMV research, charity work and health care professionals come together to try and improve care for children with CMV.
The NHS networks have published the East of England guidelines currently being updated (https://www.eoeneonatalpccsicnetwork.nhs.uk/wp-content/uploads/2022/02/cCMV-EoE-guideline.pdf ).
There is much to be hopeful for, that in the future fewer families will be affected and more will be available to support children.
Olive was born in February 2020. After a difficult pregnancy with HG we were relieved she was here, but a lockdown and more problems quickly followed! It was obvious very early to me that something wasn’t right, we sought help but it wasn’t clear what was causing her difficulties or if she was just a ‘late developer’ which we were frustratingly told on endless occasions.
Olive was 18 months when we finally had a diagnosis of profoundly deaf, my Mum and I had a glass of champagne to toast! It’s not necessarily something that most parents would celebrate but after months of shouting from the rooftops that something was very wrong and the all consuming worry of what else might be the cause of her behaviour (a seeming lack of eye contact, desire to communicate or any reaction to our voices) it was a relief to finally have an answer and a subsequent plan of action for her to have cochlear implants. This diagnosis was quickly followed with confirmation that congenital CMV caused her deafness, which we found a much more difficult diagnosis to process and accept. A quick google of CMV with no factual information will terrify any parent! But it explained so much of the previous 18 months and opened up the doors for further testing and more diagnoses of a balance disorder, severe hypermobility, sensory issues and recently a potential speech production issue. All of which made total sense!
Olive is now 3 and a quarter and what a journey it has been. Having to take a career break to become what felt most days like a full time carer rather than a mum, with endless appointments (averaging 7 a week at one point!) while juggling an older sibling, therapies and the non-stop fighting for NHS services which should be a given but sadly are not. The best decision we made, advised by our amazing teacher of the deaf, was to throw ourselves into learning BSL (British Sign Language). At 12 months Olive used a few signs and now at 3 and a quarter she is chatting away in sentences which everyday amazes us, and we are excited to continue learning this beautiful language. We still have no idea if we will ever hear Olive use her voice to say Mummy or Daddy but we are so happy she has a language she can use to communicate. She attends two deaf nurseries which are both amazing and it’s great to see her so happy. Every day we are blown away by tiny milestones that most parents take for granted but we never knew if she would reach. We are very proud of our beautiful, funny and very resilient little girl!
Just three days later, Reina was born, and while the medical team was aware of the issues with the scan, she appeared from the outside completely healthy. She showed no sign of genetic abnormalities or signs of any distress, passed all her newborn screening checks and so we went home with our lovely baby. It wasn’t until she was nearly two weeks old that the blood test results came back showing the CMV infection. We went back into hospital for four days to have further tests and scans, including an MRI. The MRI showed that the virus had done damage to the white matter of her brain, and so she began a 6-month course of valganciclovir to fight off the infection.
Although she had no complications from the medication, Reina was clearly delayed in meeting her early milestones, and she began physical therapy at eight months old. She got an official diagnosis of cerebral palsy at around 18 months. Reina still has regular audiology and
optometry appointments to check that there is no deterioration in her hearing or vision, though so far she has not shown any loss to either. She also has physio therapy and speech and language sessions to help her progress, which we are pleased to say are helping her
tremendously. She is now two and a half years old, and though she still cannot walk unaided, she’s constantly pushing herself to do more and be part of the world around her. She feeds herself, crawls confidently everywhere, and does her best to keep up with her older sister. She is a ray of sunshine and puts a smile on the face of everyone she meets.
Reina is a fantastic example of how helpful early detection of CMV can be. Had it not been for the scan and blood tests that followed, we might not have known about her condition until it was too late to begin treatment. She showed no exterior physical symptoms at birth, and
passed her newborn hearing screening without issue. Because it was detected early enough, she was able to get the very best medical intervention available. She’s also had an extraordinary team of people caring for her since her birth, and it has no doubt made a positive difference in her quality of life.
I only wish that someone would have told us about CMV during pregnancy. Having an older child who was in nursery and two parents working in a school environment with young children were both risk factors we were unaware of at the time. No one ever said don’t share cutlery or kiss a toddler while pregnant. I now tell any friends or coworkers who are expecting these things, but I hope the word will spread beyond those with direct experience of the disease. We hope that with wider awareness of the disease, fewer people will find out about CMV the way we did.
Over the last 10 years, I have been fortunate to collaborate with a range of highly talented and wonderful people from various specialities to investigate how best we can diagnose and treat cCMV. This has involved writing national treatment guidelines, conducting research to show it is feasible to integrate cCMV testing within the newborn hearing screening programme and doing surveillance studies to better understand how any future CMV vaccine could be implemented.
Our understanding of cCMV remains limited despite it being the most common infection passed from mother to baby and a leading cause of neurodevelopmental impairment in childhood. My day job is to help look after infants with cCMV and this directly informs my research interests which are to find the best ways to treat and protect the most vulnerable from the virus.
me very determined and taught me never give up. I am very focused on sport and have run lots of 10k runs and four half marathons. I have raised lots money for deaf charities and in the future I would like work in disability sport, maybe as a football coach. My message is CMV causes problems but don’t give up ,have confidence.
In 2018, I was pregnant with our fourth child, during our pregnancy my husband had become unwell and was undergoing many investigations. During this time one of the results confirmed that he had an active CMV virus. Whilst this did raise some questions as to the risks for our pregnancy, there was little or no advice offered. It was not until we met with an infectious diseases specialist that he
recommended that I was tested to rule out a current primary infection. Thus, beginning our CMV journey, I was tested at 24 weeks pregnant for CMV due to this exposure, a diagnosis of a current infection was confirmed, the hospital then looked back to my booking bloods which confirmed this was in fact a primary infection and was most likely to have occurred at around 10 – 14 weeks in our pregnancy. This then triggered what can only be described as a tidal wave of the unknown, a vast amount of referrals were made, detailed ultra sound and 3D scans were arranged, an MRI, and many discussions about options for an amniocentesis and treatment pathways.
Our son was born at 37 weeks, as we were aware of CMV in the pregnancy, George immediately began on a CMV pathway and underwent testing to confirm cCMV. Once cCMV was confirmed he then underwent screening for ophthalmology, audiology, liver and brain ultrasounds, an MRI of his brain under sedation and all of this before he was 5 days old. Our story though is a lucky one, George was found to have some brain calcifications at birth but all other tests returned normal and he was discharged by CMV specialists when he was under 1 years old. He continues to be monitored by audiology until he is 5 years old due to the increased risk of hearing loss associated with cCMV. I am very grateful that George is on this pathway and that he continues to be monitored closely as this provides reassurance to us in what began as a very stressful journey.
From a midwifery point of view, I could not believe how very little I knew about CMV, and the risk reduction measures that we should inform women and their families about. Especially, for those who are higher risk such as those that have toddlers at home or work in an early years setting due to the high transmission rate of CMV from toddlers. Simple hand hygiene measures, not sharing utensils, avoiding kissing toddlers on the mouth are just some of the steps that we should have taken that may have avoided this virus affecting George. However, even though I had 3 children in a nursery setting at the time of my pregnancy I was not aware that they posed a bigger risk to me in my pregnancy than cat litter or soft cheeses which I as a professional myself had spoken to women about but sadly have never spoke about the risks of cCMV. This was a huge learning curve for me professionally. As midwives we strive to protect and care for women and their families and we always endeavour to educate and prevent risk, however, we do not talk about CMV. Why? Is this because of lack of awareness and education? Are professionals worried about talking about something that they themselves don’t really understand in the worry they won’t be able to answer questions they may be faced with? Therefore, I am so delighted to see that the new NICE Antenatal guidelines have stated that CMV should be discussed with women as this now places onus on professionals to educate themselves in this virus.
As a trustee, I joined CMV Action in the winter of 2019, in a way to try and help raise awareness and educate professionals and the general public of this virus. As a professional myself I could not believe the lack of awareness, but also to provide support and advice for other families that have been affected by cCMV. I continue to work as a volunteer trustee for this small charity in any way I can to promote the CMV Action moto of educate, eradicate and vaccinate against CMV. The charity is working hard to promote awareness, to offer support for professionals and the general public whilst being supported by medical advisors. Big steps have been taken by many of our worldwide counterparts and strives forward for screening have been actioned in many countries/states around the world. However, here in the UK there is no screening for CMV therefore we must continue to promote awareness and prevention until screening is an option.
Cian was born full term and we were relieved he was 7.04lbs. I thought that all was fine and was delighted with him. I did notice that he was not responsive when I held/tried to feed him but he was newborn so I did not think too much of it. I could not wait to go home after all the stress from the pregnancy, but I needed a midwife check on the baby before we could do so. During this check, our midwife realised Cian had a pale rash all over his body and reduced oxygen levels. I was told Cian would be transferred to hospital by ambulance just to make sure everything was ok.
Once we were at hospital it was apparent things were serious. Cian was admitted into intensive care and treated for sepsis. He was very ill but he started to respond to treatment within a couple of days. However, his bloods revealed a very low platelet count requiring an urgent blood transfusion. Cian was tested for so many different illnesses and underwent numerous blood tests, lumber punctures and scans. One of these tests revealed Cian was positive for CMV.
Hearing and sight checks in the neonatal unit were positive but Cian’s brain scan revealed damage from the CMV and that he had suffered a brain haemorrhage. We were terrified and did not know what the future held. We were very lucky that Cian was taken on as a patient of
Great Ormond Street Hospital at 2 weeks old and he has received excellent care. Cian’s CMV viral load was high and he was started on six months of valganciclovir to try and stop any further damage from the CMV. We were told the medicine was very strong and had lots of side effects, including destroying Cian’s immunity, but we felt we had to take the chance.
Cian loves life; he is very happy and most people would not notice anything different about him but he has his challenges. We must have attended hundreds of medical appointments during his (almost) three years of life. He is under 11 different health services. Cian has global delay in his development, and still only has about 8 words but he is desperate to talk so I think he will. He has struggles with his balance and coordination and did not walk until he was 2. He regularly falls over but gets up and keeps going! Cian has cerebral palsy but is an amazing climber. He has significant difficulties with eating which our consultant has told us is common with CMV children and he still has very limited food acceptance, and needs food replacement drinks. So far Cian seems to have retained his hearing and the loss he has experienced appears to be due to glue ear which grommets have helped with. He is under investigation for problems with his liver which may or may not be linked to CMV.
It is incredible that nobody has heard of CMV. I see now that we are lucky Cian was so ill at birth and we had an amazing midwife who picked up on the subtle signs he was unwell. Being in hospital meant Cian was tested for CMV and started on medication to try and stop the damage caused to Cian’s brain. If we had gone home, like many other parents have done with their new baby not knowing something was wrong because there is no routine testing for CMV, Cian would not have benefited from that medication.
This is a regular part of my job, with consultations, ultrasound assessment, performing invasive procedures to diagnose the infection or to work out how severe it is, providing a second opinion to families or other healthcare professionals across the UK and globally, as well as responding to queries from pregnant women contacting the CMV Action charity. I always want to assist whenever I can, to help improve the outcomes and experience of these parents.
In my opinion, it is very important to raise awareness among the public and healthcare professionals about congenital CMV infection, its prevention and treatment. We can raise awareness through disseminating knowledge, shared learning and updating healthcare professionals at every opportunity, whether webinars, educational courses or study days. I have led on the Royal College of Obstetricians and Gynaecologists (RCOG) Scientific Impact Paper on congenital CMV infection, highlighting recent evidence from research and controversial areas. I am currently updating this guidance document, taking into account the most recent evidence, in particular focusing on
treatment with valacyclovir and the best approach to assess the severity of congenital CMV infection. I also led on the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) guideline on congenital infections, with a special focus on the role of ultrasound in determining whether the baby will be affected/harmed by congenital CMV infection, whether to offer treatment and what evidence there is to support it; and when not to offer some interventions during pregnancy, as they are not supported by robust evidence.
Raising awareness among the public needs a different approach. I believe that this should target everyone in the community, not just pregnant women. Even though we have celebrated our success in including CMV counselling at the first pregnancy booking visit in the NICE antenatal care guideline, even that is likely to be late to start informing pregnant women about CMV during pregnancy; booking takes place at approximately 10 weeks, by which time it might be already too late. We know that CMV infection during the early stages of pregnancy is most associated with harm to the baby, so we need to ensure that women are informed even before pregnancy. I organised an ISUOG educational course and an RCOG study day on congenital infections, where several talks were dedicated to congenital CMV infection prevention and treatment. In both meetings, I ensured that we had representation from our patients and CMV Action charity, as I strongly believe that we need to work closely together to improve the current counselling, management and treatment of these families and babies.
Research is key to improving the way we provide clinical care, improve the outcomes of these pregnancies, and save babies lives. Research is an integral part of my everyday practice, whether conducting studies, publishing research papers, reviewing studies for publication, collaborating with colleagues at my workplace or globally in large research trials. Over the past few years, I have been a member of a team that led on a number of research studies addressing prevention and management of congenital CMV infection, e.g. the RACE-FIT study. In this study we developed an educational video that aims to reduce the likelihood of women becoming infected with CMV during pregnancy. We also tested more than 1000 pregnant women for CMV infection early in pregnancy. I counselled all those who tested positive for
the risk of congenital CMV infection and its implications. Through this research we learned many lessons, as well as listening to women’s views about congenital CMV. I also published several studies on the value of fetal brain MRI, on the level of CMV virus in pregnancies with congenital CMV, and on the benefits and harms of offering valacyclovir treatment in pregnancy.
By summer 2023 I will have been a doctor for 40 years, and nearly the last thirty have been spent as a member of the Paediatric Infectious Diseases Team as St Mary’s in London. Over the last 15 years, I have looked after many babies born with congenital CMV, and have wished so much that I could have done more for them and their families.
Testing for CMV is complicated, but we could test pregnant women, or women planning to get pregnant. We could also offer, interventions to reduce the risk of infection, as well as treatment for women who become CMV infected in the early months, when the risk of brain damage and hearing loss from CMV is greatest. In many European countries testing and treating for CMV in pregnancy is becoming the norm – we should not be left behind in the UK. There is lots of evidence, and there are cost effectiveness studies as well, that highlight how these interventions can work so well for prevention of CMV infection in pregnancy. We all need to work together to raise awareness about what this common virus can do.
In the UK today, one in 200 babies is born with congenital CMV infection, up to 10% are severely affected and diagnosed at birth, and at least half of them will have hearing loss and many also brain damage. Of the other 90%, up to 10 % may develop hearing loss, either at birth or later on, and they may also have problems with learning and communication. We have no crystal ball, and cannot predict at birth which babies will have problems and which will not, and this is so hard for parents to live with day to day. I am so aware of the stress that I cause these little babies’ new parents when I explain to them about the uncertainties, but I think its important for them to know what may lie ahead. Currently I have a research psychologist working with me so that we can learn more about how to better support families in those early months. We can treat babies to reduce the risk of progression of hearing loss and to protect brain function, but the treatment is not easy, with lots of blood tests. Best of all would be to give women the opportunity to avoid infection in pregnancy, if possible.
In the UK, CMV ACTION has played a great role in raising awareness about congenital CMV, and the website has very good and clear information which can be translated into lots of languages. The power of CMV ACTION lies in the fact that it is driven by families who have experienced at first-hand what CMV can do. We need to make sure that women and their healthcare workers know about CMV in the same way they already know to avoid soft cheese to prevent listeria, or avoid cat litter to prevent toxoplasmosis, both much, much rarer infections than CMV. Women need to know that they can avoid CMV in pregnancy by washing their hands after contact with the saliva or urine of young infants and children, this really can protect them (see details on the CMV ACTION website). Sometime soon I will retire from the NHS, and before I go I would really love to say GOODBYE to CMV. Ironically though, to get there, we need to make sure that everyone knows more about CMV!
Hazel is our almost 12 year old daughter with an infectious optimism. She has a knack of making everyone around her smile and feel great about themselves. She truly is a gift. Her life is by no means easy, and as a family we navigate many challenges. At times it can feel overwhelming, exhausting and relentless but mostly we spend our days appreciating triumphs.
The other day Hazel and I were walking to the car and she was chatting, as usual, to distract herself from the discomfort she feels when walking. She asked me if my life would be more stressful if she had a twin. I joked that it might be quieter for me if she talked non stop to her twin instead, but if her twin was equally a chatter box wanting my attention then yes, it would be stressful! We laughed together. She told me what she imagined her twin sister to be like….they would share all the same interests like music, dancing and performing. I asked Hazel if her twin would be deaf, like her. She said ‘no, I’d want her to be hearing so she could hear me and listen to me’. I pointed out to Hazel that she never stops talking and listening, though she is profoundly deaf (she has had cochlear implants from 15 months old).
Hazel failed the newborn hearing screening test and our journey started there. Her brother, Alistair, was about to turn 2. Initially our time was spent in and out of audiology clinics. Hazel’s Teacher of the deaf frequented our house and I spent a lot of time reading about parenting a deaf child. Adam and I researched and aimed to navigate our way through family life feeling informed and empowered. If our baby couldn’t hear we would learn BSL and find a way to communicate. We heard about the connexin 26 gene and assumed it was in Hazel’s DNA to be deaf. It was always meant to be this way. In a way we felt privileged to have this little deaf baby to guide through life. She came into a loving unit of 3 and was most wanted.
A few months on and hospital visits weren’t confined to audiology rooms. Hazel had reflux, then silent reflux, she was always constipated, she was always floppy and showing no sign of being able to keep her head up. She was always crying. Despite frequent scans during my pregnancy, due to my baby’s head measuring small, no medics reported concerns after her birth. The birth was natural, with no complications. She was small for full term (and compared to her brother) but not alarmingly so. It was suggested that I have a small head so this feature was probably hereditary. The paediatrician/Head of newborn hearing screening made some comment about showing no signs of CP when he confirmed she was moderate to severely deaf. By 5 months he told us she was profoundly deaf and by age 7 an orthopaedic consultant confirmed she had cerebral palsy.
We laugh now at how long we waited for the CP diagnosis as it was very obvious from her first few months of life. We still cried when it was confirmed. When you get told your child is developmentally delayed you cling to the hope that one day they will just catch up. There’s no catching up to your physically able peers when you have cerebral palsy. We then knew her life would forever be more of a struggle.
Back to 7 month old Hazel. Yes, we would like to have tests done to see if the cause of her deafness was genetic or other. First test, urine sample test for CMV. Positive. Blood spot test next. Congenital CMV confirmed. So what is cytomegalovirus and who has heard of it? Turns out none of the health visitors, physios, baby massage lady (H still cried with tummy pains) or nurses we came in contact with. The teacher of the deaf knew about it, recognising it as the leading cause of deafness that’s not hereditary. Everyone else, clueless. We came home from hospital with the list of possible symptoms and told its a ‘watch and wait’ scenario. She might present with vision difficulties, epilepsy, a variety of health issues, learning difficulties, behavioural difficulties, be slow to reach physical milestones. The latter was already apparent.
This is when my optimism faltered and other feelings took over. I still had the same beautiful deaf baby in my arms but something shifted. Our baby wasn’t designed to be deaf. It wasn’t in her genetic make-up. I caught cytomegalovirus in pregnancy and this changed the course. It changed who Hazel was going to be and how our lives would be from now on. It felt harder to accept. I felt responsible. This is something I have struggled with over the years. So in 2011 who was looking for the signs? During my frequent scans…at her birth. If it had been detected earlier would things be different? Questioning this then brings on a heavy guilt. Why would I want my child to be any different? Well, 12 years on I don’t. I am now a qualified and experienced teacher of the deaf, supporting teenagers in a mainstream school. My husband Adam works for Guide Dogs. and Hazel's brother Alistair is the most accepting, non-judgemental teenager. Our family understands challenge, we know about disability, about perseverance, hope, strength, love and humility. The days I don’t wish Hazel to have her deafness, alongside her learning difficulties, speech and language disorder and her CP are the days when society’s barriers are firmly in the way. But strength seems to feed strength and Hazel powers us up to battle with schools and councils to get what she needs. She radiates positivity, even when she is so fatigued that her speech is slurred and she can’t sit up straight. This is inspiring.
So back to our conversation about her imaginary twin. Hazel said that although they would be different, as she would be deaf and her sister hearing (I think she wants the upper hand on that one, she is super proud of her deaf identity), absolutely her sister would have cerebral palsy. Hazel is totally content with who she is and all that comes with it. She is now at a school for the deaf, where learning is more accessible and she is appropriately challenged. She has performed in the Shakespeare schools festival recently. Once she could walk she started dancing, discarding her splint and risking the falls (brief pauses for Botox in to her calf). Sometimes a wheelchair is necessary but other times she will challenge herself to run for charity, 1k, 2k, she’ll keep pushing herself. Hazel wore nappies when she started school, she didn’t walk independently until she was 5 years old. We don’t dwell on any of this. It has been hard but it has been rewarding and continues to be. Hazel looks at other young people with differences and sees them as role models. It is a beautiful thing to now see other children look up to her. We are very proud parents indeed and move towards the teen years knowing there will be countless more triumphs ahead.
I am frequently asked: why don't we yet have a CMV vaccine? Following the Covid-19 pandemic success of designing and developing a vaccine against SARS Coronavirus 2 in record time, let's compare the latter with the former. All licensed viral vaccines work by inducing antibodies against the surface protein of a virus so that they neutralise infectivity. A person is given an antigen (the name is short for generates an antibody) derived from the virus and the immune system responds by producing antibodies. Sounds simple, doesn't it? In practice, there are many scientific, technical, financial, organisational and regulatory hurdles to be overcome before a vaccine candidate can be declared to be both safe and effective. Yet, the pathway to addressing these hurdles is well known and frequently trodden by vaccine manufacturers.
We can now be confident that teams of people could deploy their skills efficiently to produce a vaccine against any new virus that causes acute infections (those that last a short time and where the virus disappears from the body as the patient recovers). Unfortunately, CMV does not behave like this. Although the patient may appear to recover from the acute phase of primary CMV infection (and may not even have any symptoms to report) the virus does not disappear. It establishes latency in cells within the body, lying low until it decides to reactivate weeks, months or years later, evading host immune responses as it does so. These so-called recurrent infections may cause as much illness as the primary infection does; indeed, most women delivering babies with congenital CMV infection have had recurrent infections during their pregnancy.
How does CMV avoid immune responses? The answer to this is becoming better understood but is very technical. In short, CMV achieves this by committing many more of its genes to evading immune responses than it does to producing the virus particle. These immune evasion genes antagonise every one of the responses that the human immune system throws at CMV. In addition, CMV avoids the battlefield of the fluid outside the cell, which is full of antibodies, and instead spreads laterally to infect neighbouring cells. So, is everything lost in the battle to make a vaccine? The answer is no, but it is requiring more thought and ingenuity than is needed to make a vaccine against a virus, like SARS Coronavirus 2, that only causes acute infections.
To begin with, a protein on the surface of CMV (called glycoprotein B) which is equivalent to the spike protein of SARS Coronavirus 2 was used in a vaccine. Clinical trials showed that it provided modest protection against CMV (about 40%-50%) in women of childbearing age, in adolescent girls and in older males and females awaiting transplantation. I organised the last of these 3 trials because we already monitored the patients after transplant for the presence of CMV and how much CMV was present (the viral load). We could then ask how well the viral load had been reduced in recipients of vaccine compared to those randomised to receive placebo. We could also look at the blood samples from these patients and work out how the vaccine had provided some protection. This laboratory work took more than a decade after the clinical trial was completed but we could then report; 1) the vaccine worked by producing antibodies; 2) these antibodies did not neutralise the virus; 3) one type of antibody inhibited CMV fusing to cells; 4) another type of antibody prevented CMV spreading from cell to cell; 5) antibody against one antigen acted as a decoy to divert the immune system away from the parts of glycoprotein B that would provide protection. So, although CMV is complex, we're getting a handle on how to prevent infection so the results of clinical trials will tell us which antigens of the virus should be included in a vaccine.
A large clinical trial from one manufacturer has recently reported its headline results in an abstract and we look forward to reading the details in a full scientific paper. The abstract reports partial protection of seronegative women (those who have not had CMV infection in the past) from a vaccine containing all proteins of the virus, including several surface proteins, glycoprotein B plus another one called pentamer. Another clinical trial from a second manufacturer is underway using just the pentamer plus glycoprotein B. If these two large trials only give partial protection, then the antigens mentioned in 3 and 4 above can be added to vaccines and further clinical trials conducted. Manufacturers will want to use the minimal number of antigens that give a vaccine that is both safe and effective, so a careful stepwise approach can be expected.
Although this will all take time, members of the public could meanwhile let us know what type of randomised, placebo-controlled clinical trials they would find acceptable. It is possible that seronegative women, seropositive women, males and females awaiting transplant and toddlers of both sexes will be invited to take part in the future. Let us know what you think.
As Coordinator of the group I have contact with many families whose children are deaf due to CMV, a virus that can result in a wide range of difficulties from deafness with very little else to those with complex challenges. This can be devastating not only for the child but for the whole family. CMV Action provides a wealth of information, experience, support and a ray of hope and light as they search for the best ways to help their child.
CMV is one of the leading causes of deafness in children and of childhood disability and yet many people are simply unaware of its existence. Not only does CMV Action help families directly but they also campaign to raise awareness of this virus, highlight ways to reduce the risk and also encourage further research into developing a vaccine.