Hantavirus vaccine exists but is ineffective in person-to-person transmission

While the scientists behind the Covid-19 vaccine developed it in record time using messenger RNA (mRNA) technology, the hantavirus vaccine is progressing at a different pace.

There is one vaccine that has existed in Korea since the 90s, but it has low immunogenicity. It is ineffective against the variant that attacks the lungs, such as the Andes strain detected on the MV Hondius cruise ship.

In addition, use of this vaccine does not have European authorisation, as the Spanish society of immunology states.

The first case in Spain, although in involving transmission from rats, concerned "an 82-year-old woman who presented with flu-like symptoms including fever, lower back pain, vomiting, haemorrhaging, acute renal failure, electrolyte imbalances, respiratory distress, hypotension and shock". The case appeared in a University of Alcalá study, published in the Revista Clínica Española journal in 2002.

Then, there was the case of "a 69-year-old man" who tested positive. The authors noted that "interest in the diagnosis of hantavirus infections began in 1993".

Although Spain confirmed the presence of the hantavirus more than 30 years ago, with rodents as the reservoir of the infection, there has not been a serious public health problem. The situation is similar in European countries and North America, with the presence of strains that have virtually no lethality.

Therefore, there have been no real economic incentives for pharmaceutical companies. The cruise ship outbreak, however, with more than 20 nations aboard, and the memory of the Covid-19 pandemic, have given pharmaceutical companies a boost in their respective vaccine research.

The continent most at risk is Asia, especially China, where more than 1.5 million cases have emerged in half a century, with almost 46,500 deaths, according to the US Centers for Disease Control and Prevention (CDC). Meanwhile, in South Korea (the country from which the virus takes its name, from the Hantan river), there are about ten deaths annually, out of approximately 400 cases, according to the Korean Ministry of Health (KDCA).

Research into a vaccine began precisely in Korea. Two years ago, Korea University partnered with pharmaceutical company Moderna to develop a hantavirus vaccine based on messenger RNA, similar to the Covid-19 vaccine. The university's vaccine innovation centre called it a "comprehensive collaboration with the global pharmaceutical company" in July 2024.

The country is seeking to curb the haemorrhagic fever that affects young men in their 20s and 30s who are performing their mandatory military service, according to Korea University. Now, with Moderna, they aim to find "a new vaccine effective against a broader range of hantavirus strains".

Specialising in the development of "mRNA drugs" that "stimulate the immune system", Moderna designed the Covid-19 vaccine in a few weeks and less than a year after knowing the virus's sequence. It approved it in December 2020.

Moderna's interest in developing a hantavirus vaccine, which it confirmed this week, has caused its stock to rise by five points. The company, however, first expressed this intention in September 2023, when it had an initial "research" approach with Korea University.

"The Vaccine Innovation Center provided Moderna with information on the hantavirus antigen sequence and Moderna provided mRNA material from that information," Moderna sources said.

Currently, "these efforts are still in their early stages but they are ongoing", as Moderna stated after the cruise ship incident.

Meanwhile, the European Medicines Agency (EMA) has requested that drug developers prioritise hantavirus research and tasked the Emergency Task Force (ETF) with mapping these centres, including pharmaceutical companies like Moderna, particularly those developing antivirals, monoclonal antibodies and vaccines against hantavirus. The EMA says it is prepared to support the development of hantavirus vaccines and treatments.

Although the WHO (World Health Organization) has ruled out a pandemic in this case, Korean scientists are working on a "rapid" project to develop vaccines within 200 days "after the start of a pandemic". Pharmaceutical companies are in the race for an antidote to a virus that has reminded the world of the fears during the Covid-19 pandemic.