“Hantavirus is simpler, more robust, than Covid-19”“This statement clarifies a little-known scientific fact,” declared Olivier Schwartz, director of the Virus and Immunity Unit at the Pasteur Institute, during the press conference held by the Minister of Health on May 12, 2026. This statement clarifies a little-known scientific fact: not all viruses are equal in terms of epidemic potential, danger, or transmission. And while the comparison with Covid-19 naturally comes to mind in these anxious times, the differences between the two viruses are significant.
With hantavirus, transmission between humans is rare
The Andean hantavirus has been known for about thirty years and is usually confined to certain regions of the globe, mainly in Latin America (Argentina, Chile, Uruguay). In these areas, about a hundred cases are recorded each year, often linked to contact with rodents, which are its main reservoir.
Indeed, when infected, animals excrete the virus in their urine, feces, or saliva. The pathogen can then remain viable in the excrement for about a month. Humans are generally infected by inhaling viral particles, for example, when cleaning a dusty, enclosed space.
Unlike Covid-19, human-to-human transmission is rare. It has been observed with the Andean hantavirus, but it requires close and prolonged contact and remains relatively inefficient. Its R0, that is, the average number of new cases that an infected person can generate, is estimated to be between 0.2 and 1.2, a maximum value very close to the point of no transmission.
Indeed, while a person infected with a virus can only infect one other person on average, the pathogen eventually dies out on its own. Whereas Covid-19 could spread rapidly throughout the population with an R0 of 3 (one person infecting three others on average), hantavirus tends to cause isolated cases or small clusters of infection. This is where experts point to a major difference: Covid-19 had a high epidemic potential, with easy transmission, while hantavirus circulates much less readily.
| Hantavirus | Covid-19 | |
| Country of origin | Argentina | China |
| Gender | Orthohantavirus andesense, or Andean hantavirus, is an RNA virus |
SARS-CoV-2 is an RNA virus |
| Animal reservoir | Long-tailed pygmy rice paddy rat | Civet or raccoon dog |
| The outbreak of infections began. | April 2026 | November 2019 |
| Mode of human-to-human transmission | Bodily fluids (sweat, saliva, tears, etc.) | Aerosols, microdroplets |
| Incubation period | Between 9 and 40 days | Between 5 and 14 days |
| Contagiousness | Low. Requires close contact. It is estimated that one person infects, on average, fewer than one other person. It is still unknown whether people who have not reported symptoms are contagious. | Strong transmission occurs several meters away. It is estimated that one person infects an average of two to three people. Some asymptomatic individuals can transmit the disease. |
| Symptoms | Lung damage and respiratory distress | Fever, cough, fatigue. Respiratory distress in the most severe cases. Long COVID can occur and last for several months. |
| Lethality | 20 to 50% of the patients | Approximately 0.5 %, but this varies according to age. From 0.01% for those under 15 years old to 17% for those over 90 years old. |
| Treatments | None. Several are under consideration. | Antivirals |
| Vaccines | In phase 1. | Several were developed from the beginning of 2020, notably thanks to a new, faster technique using the virus's messenger RNA. |
The Andean hantavirus has a mortality rate of approximately 40%
In contrast, the Andean hantavirus is far more dangerous. With a mortality rate of approximately 401 per 100,000 live births, the virus targets the pulmonary and renal blood vessels, leading to serious complications. To date, there is no specific treatment or validated vaccine.
Read alsoHantavirus: the search for treatments is still in its early stages
However, experts remain confident. “We have a good understanding of the virus’s structure, which facilitates the development of antiviral treatments and vaccines. These efforts will obviously be intensified.”" said Olivier Schwartz during the press conference.
Genomic analyses are underway, and the complete sequencing of the virus should be available in the coming days. Many questions remain, one of the main ones being the status of infected individuals who do not show symptoms.
In the case of Covid-19, it turned out that some of them could unknowingly transmit the virus. Given the small number of cases, the situation with this Andean hantavirus is still unknown. (Editor's note: The editorial team will update this article based on future results.)
With Laetitia Maouchi
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