What the Hantavirus Outbreak On the Cruise Ship Really Means

    On May 2, a cruise ship full of citizens from many countries, including the US, reported an outbreak of a severe illness with two deaths and one critically sick. The incident was later confirmed to be an outbreak of hantavirus among the ship’s passengers. 

    The World Health Organization (WHO) has released multiple statements clarifying the scope of the outbreak, including words from Maria Van Kerkhove, the organization’s Director of Epidemic and Pandemic Preparedness and Prevention: “This is not COVID. This is not influenza.” The United States Center for Disease Control (CDC) has given similar statements.

    So, what exactly is hantavirus? This viral infection is not new—cases were documented in Korea in the 1950s, during the Korean War. In 1978, the culprit—rodents—were identified. There have been small, “contained” outbreaks in the US starting in 1993, including a notable one in the Four Corners region of the United States. 

    For the sake of scientific clarity, it is worth noting that the hantavirus isn’t the actual culprit, much like how COVID-19—and not the coronavirus—was the direct reason for the pandemic starting in 2019. Hantavirus pulmonary syndrome (HPS), caused by some hantaviruses, is the actual illness. This respiratory disease is incredibly painful and debilitating. 

    The Andes strain of the virus, thusly named due to its identification in South America, is the variant that caused the outbreak on the cruise ship last month.

    The fatality rate of hantavirus and HPS is quite high, at approximately forty percent for anyone who contracts it, compared to COVID-19’s pre-vaccine fatality rate of seventeen percent among hospitalized patients. Three unfortunate deaths were reported and confirmed out of eight cases, according to the WHO.

    However, the CDC has rated hantavirus in the category of lowest pandemic-causing probability among monitored viruses, a conclusion supported by other sources. Therein lies the good news of the situation; the Andes strain now circulating in the news is the only known strain of virus that can even spread from person to person, while the others must be through direct transmission from an infected rodent, its fluids, or its feces. Respiring small molecules from fluids and feces is the more common method of transmission. Neither method of transmission is common in comparison to other respiratory viruses, and hantavirus has had far fewer overall cases—a total of under nine hundred reported from 1993 to 2017 in the United States.

    The Andes virus is much harder to transmit. A Stanford Medicine article highlights a quote from Jorge Salinas, Stanford Assistant Professor and Medical Director of Infection Prevention, detailing how the hantavirus is completely different from other viral infections in the efficiency of transmission. “There are respiratory viruses like flu and COVID-19 that are incredibly efficient at transmitting [from] person to person. That’s what they have evolved to do. Hantavirus just isn’t like that. It can jump to a few people after close contact with an infected, symptomatic individual, but we don’t expect it to spread very far.” The lack of a vaccine approved by the Food and Drug Administration for any hantavirus strains, however, means that any outbreak must be taken seriously. Masking while cleaning rodent feces or residue is a good precaution, and monitoring the stages of vaccine production is a great way to stay in touch with how scientists are handling this virus. 

    Hantavirus gives no indication of causing the next COVID-style pandemic, but is a legitimately harmful virus that leads to a severe respiratory syndrome. The scientific community and the public will continue to monitor this virus’s progress, among the many others in our world, but don’t feel the need to wear a mask the next time you step from your house into the world—HPS is not knocking on your door.