The death of a newborn baby with Lassa fever in Luton is a grim reminder of the global threat posed by deadly infectious diseases. Three cases have been confirmed in England â€“ the first time the acute viral illness normally only seen in west Africa has emerged in the UK for 13 years.
This weekend, officials from the UK Health Security Agency are closely monitoring hundreds of people identified as potential contacts of the three cases. The Guardian has learned many of these individuals will continue to be monitored for the rest of the month and into March.
The NHS is also performing risk assessments of staff and patients who were in the same areas as the Lassa fever patients in Luton and Dunstable University hospital and Addenbrookeâ€™s hospital in Cambridge.
Although most people with the disease will make a full recovery, severe illness can occur in some and one in every 100 infected will die.
No further cases have been identified to date. But global health experts say the return of Lassa fever â€“ at a time when the UK is still fighting off another deadly infectious disease, Covid-19 â€“ is a sign of worse things to come.
â€œThe three confirmed cases of the potentially deadly Lassa fever in the UK, now very sadly including one death, are a stark reminder of our interconnected world and the need to continue to invest in outbreak preparedness and response efforts,â€ said Dr Melanie Saville, the director of vaccine development at the Coalition for Epidemic Preparedness Innovations (CEPI).
Globally, the number of people contracting infectious diseases such as Lassa fever, the harms they can cause and their abilities to move rapidly from one side of the world to the other are growing â€“ and for a variety of reasons, according to Saville. â€œEmerging infectious diseases are increasing in prevalence, severity and spread as a result of climate change, global transportation and human encroachment into previously isolated areas,â€ she said.
The growing threat posed by deadly infectious diseases, Saville said, underlines the â€œurgent need for vaccinesâ€. CEPI is now advancing the development of six Lassa fever vaccines. Three of these â€“ developed by Inovio Pharmaceuticals, the International Aids Vaccine Initiative (IAVI), and Themis Bioscience â€“ are the first in the world to enter clinical trials. The ultimate goal, Saville said, was to produce a licensed Lassa vaccine for routine immunisation.
To enable this to happen, the largest-ever Lassa fever study, called Enable, has been launched to provide a more accurate assessment of the incidence of Lassa fever infections in west Africa. More than 20,000 people are being recruited to take part in the study, which will provide key information to help guide future late-stage Lassa vaccine clinical trials and potential vaccination strategies following licensure of a product.
Some scientists have raised concerns that lessons have not been learned from Covid-19 about the need to properly fund the development of vaccines for other deadly infectious diseases.
Prof Dame Sarah Gilbert, one of the creators of the Oxford/AstraZeneca vaccine, warned in October her team was struggling to raise the money needed to develop vaccines against diseases including Lassa fever.
â€œWeâ€™ve actually gone backwards in terms of the work weâ€™re doing on development of vaccines for the outbreak pathogens before the pandemic,â€ she said. â€œItâ€™s just really slowed right down. Trying to get that moving again is really difficult and the funding still isnâ€™t there to move that on.â€
That message might slowly be getting through. This week, the UK government said research into vaccines against deadly infectious diseases would be backed by a new Â£10m fund. The UK Vaccine Network will provide grants for 22 projects aimed at tackling severe illnesses in low- and middle-income countries. They include Â£498,000 to DIOSynVax to develop its vaccine against Lassa fever, Ebola and Marburg virus disease.
The real hope, though, according to Saville, is the development of a vaccine that could be prepared for use against a new disease that has not yet emerged, such as a new member of the Lassa feverâ€™s Arenaviridae viral family. Recognising that new viruses from this family could emerge in the future with greater transmissibility and/or fatality rates, experts are already using the work on the Lassa vaccine to guide the creation of a prototypic vaccine for use against the Arenaviridae family.
â€œThe idea here is that this prototype vaccine could be ready to be pulled off the shelf and swiftly adapted next time a novel Arenaviridae virus emerges,â€ said Saville. â€œThat way, we donâ€™t lose valuable time creating a new vaccine from scratch.â€
The good news is, for now at least, Lassa fever poses very little risk to people in the UK and is nowhere near as dangerous as Covid-19, which has killed 160,000 in the UK the past two years.
â€œLassa fever is a serious infection, but is nothing like as infectious as Covid-19,â€ said Dr Michael Head, a senior research fellow in global health at the University of Southampton. â€œPrevious studies have estimated the R number of Lassa to be roughly between 1.0 and 1.6. The original wild-type coronavirus at the start of this pandemic had an R number of about 3, and the variants have become increasingly infectious.
â€œOf course, any Lassa cases within the UK are of concern. However, we wonâ€™t be seeing transmission anything like the scale we have with the Covid-19 pandemic, and the risks to the wider public are very low.â€