The deadliest Ebola outbreak on record, and a vaccine built for the wrong virus

The outbreak nobody has a vaccine for

The Ebola outbreak in the Democratic Republic of Congo is on course to become the deadliest ever recorded. Tedros Adhanom Ghebreyesus, head of the World Health Organization, said this week that at its current pace it would eclipse the 2014-16 West African epidemic [1]. That outbreak killed at least 11,000 people. Congo’s has caused at least 4,300 cases and more than 2,000 deaths since it was declared on 15 May [1].

The declaration came late. Health officials now say the virus was spreading by February, at least three months earlier, and was first mistaken for malaria or typhoid [1][2]. “We are chasing the virus, the virus is ahead of us,” said Mohamed Janabi, the WHO’s Africa director [2]. Because of insecurity in the east of the country, health workers reach only about 30% of cases; most of the rest die at home [2]. The WHO says it hopes to reverse the spread within three months, and is careful about what that means: bringing transmission under control, not ending the outbreak [1].

The hardest fact is pharmacological. This outbreak is caused by the Bundibugyo species of Ebola, a rare one that has surfaced only twice before, in 2007 and 2012 [1]. There is no approved vaccine for it and no recognised drug to treat it [1][2]. The one licensed Ebola vaccine, Merck’s Ervebo, was built against a different species, Zaire, which caused nearly every past outbreak [3].

So a question that is usually academic became urgent: does a vaccine aimed at one species protect against its cousin? In late May a WHO expert panel said the evidence was too thin to even try [3]. Giving a “mismatched” shot could create false confidence, the panel warned, and if vaccinated people fell ill anyway it could damage trust in Ebola vaccination generally [3]. The evidence has since shifted. Test-tube and animal studies have persuaded scientists that Ervebo is worth testing properly in a large Congolese study [3]. Oxford researchers have separately begun a first-of-its-kind trial of a new Ebola vaccine [4].

Money is the other constraint. Oxfam’s field coordinator in Congo, Manel Rebordosa, worked the 2014 and 2018 outbreaks and says the international response is visibly thinner this time [4]. The charity links that to aid cuts, including a British decision to remove about 6 billion pounds from the overseas budget by 2027 [4].

Cells that would not die

A paper in Nature Medicine this week reports something the field has waited a decade to see. Researchers followed 38 people with non-Hodgkin lymphoma who received CAR-T therapy [5]. In CAR-T, a patient’s own T cells, a type of immune cell, are re-engineered in a lab to hunt cancer and then put back. In five of eight long-term responders, the engineered cells were still detectable seven to ten years after a single infusion [5]. Three still showed the signature of ongoing activity: their normal B cells, the antibody-making cells the therapy also strips out, remained absent [5]. That is what you would see if the engineered cells were still working [5].

That is unusual biology. Most T cells that swarm to fight something are gone within weeks. Persistence at this scale suggests the cells settled into a long-lived state rather than burning out.

Two other cancer stories moved. On 13 August the FDA gave iberdomide, sold as Zenbexus, an accelerated approval - a faster clearance granted on early evidence, with a full trial still to come [6][7][8]. It treats multiple myeloma, a blood cancer, in patients who have already had at least one other treatment [6][8]. It is the first of a new class of drug [6]. It is also the first the agency has cleared on a more sensitive measure of remission: how much cancer is left after treatment, below what standard tests can detect [6][7]. It carries the agency’s strongest warning label for harm to a fetus, and lists at $29,500 per 28-day cycle [7]. And Taiho and Cullinan reported that their lung-cancer drug zipalertinib succeeded in a late-stage trial [9]. The patients had not been treated before and carried a rare fault in a gene called EGFR, which drives some lung tumours [9]. The trial was designed to detect a 40% cut in the risk of the cancer worsening or the patient dying [9].

Regulators change their minds, in both directions

Capricor’s Duchenne muscular dystrophy therapy looked finished last month, when an FDA advisory panel voted nine to three against its effectiveness data [10]. On Thursday the company said the agency is willing to look at fresh 24-month results on arm and hand function [10]. Its 22 August decision date will be pushed back [10]. The shares more than doubled, to $9.18, still far below the $19.70 they fetched before the panel [10]. Elsewhere the agency rejected ITM’s radioactive cancer therapy over manufacturing problems, despite trial data showing 23.9 months without tumour growth against 14.1 months on an existing drug [12]. European regulators accepted Pfizer and Valneva’s Lyme disease vaccine for review [11]. And PTC bought Sangamo’s Fabry disease gene therapy out of bankruptcy for $111 million, with $100 million more tied to approval [13].

A first systemic option for vitiligo

The Lancet published two phase 3 trials on Saturday of upadacitinib in adults and adolescents with non-segmental vitiligo [14]. Vitiligo is an autoimmune disease: the body’s own defences destroy melanocytes, the cells that make skin pigment, leaving pale patches [14]. No systemic therapy - one that works through the whole body rather than on the skin - has ever been approved for it [14]. Upadacitinib is a daily pill already licensed for other inflammatory conditions. Phase 3 is the large final test before approval, comparing a drug against a dummy pill in hundreds of patients.

The ageing brain turns out not to be sealed

The week’s most surprising result came from Stanford, in Nature. Scientists have long treated the brain’s immune system as a closed shop. Its resident immune cells, called microglia, were thought to be laid down before birth and then to renew themselves for life [15]. The blood-brain barrier was assumed to keep outsiders out [15]. The new work finds that immune cells from the blood enter the human brain in large numbers from middle age onward, and can take up residence as microglia [15]. “We usually think of the brain as a closed system,” said Julia Belk, the study’s first author [15]. The team came to it sideways: earlier work showed that people carrying certain mutated blood-stem-cell clones were markedly less likely to develop Alzheimer’s [15].

A separate paper in Neuron describes what happens when brain immune cells age badly. Microglia with worn-down chromosome ends enter a stalled state and release a protein that strips myelin, the insulation around nerve fibres, and impairs the neurons around them [16]. And a study of 21,462 women, published in Neurology, looked at estrogen-only hormone therapy started later in life [17]. Users had 39% lower odds of a dementia diagnosis, and 35% lower odds of Alzheimer’s changes at autopsy [17]. The authors are blunt that this is an association, not proof of prevention, and that most of these women started therapy after 70, unlike current practice [17].

Also in ageing: a Nature Medicine team trained software on 25,712 tissue slides from 40 organs in 983 people [18]. The result is a set of “tissue clocks” that estimate how old an organ looks, with an average error of 4.9 years [18].

Also this week

A 65-year-old kidney transplant patient in California had a drug-resistant E. coli infection that antibiotics could not clear [19]. His doctors treated him with viruses engineered to carry CRISPR machinery that shreds bacterial DNA [19]. Within a week his open abdominal wounds began to close and a mass on his bladder halved, from 0.74 to 0.37 litres [19]. The caveat is large: he started a stronger antibiotic cocktail 11 days before the viruses, so nobody can say which worked [19].

On the money side, Jazz agreed to buy Actio Biosciences for $820 million up front and up to $1.3 billion in total [20]. Actio’s lead drug targets a form of epilepsy that affects roughly 2,500 people in the US and has no approved treatment [20]. That deal belongs to a pattern. Nineteen private biotechs were bought in the first half of 2026, more than in any of the previous five full years, at a median of $950 million [20]. And Epicrispr raised $90 million for a treatment that uses CRISPR tools to switch a harmful gene off rather than cut it out [21].