Not every outbreak becomes the next Covid

By Dr Muhammad Amir Yunus

News of the recent Andes virus (ANDV) outbreak aboard the cruise ship MV Hondius has understandably triggered concern among many people. Reports of multiple deaths, combined with social media discussions about passengers returning to their home countries after leaving the vessel, have revived memories that many hoped had been left behind after the Covid-19 pandemic.

The reaction is understandable. Covid-19 changed the way societies respond to news about infectious diseases. For many people, any report involving an unfamiliar virus, overseas outbreaks, or international travel now immediately raises the same unsettling question: could this become another global pandemic?

But from a virology and public health perspective, not every virus behaves the same way, and not every outbreak carries the same pandemic potential.

That distinction matters.

The Andes virus belongs to the hantavirus family, a group of viruses typically associated with rodents as their natural hosts. Unlike SARS-CoV-2, which spreads very efficiently through respiratory droplets and aerosols in everyday public settings, the Andes virus has a much more limited transmission pattern. It depends heavily on a specific rodent species found mainly in parts of South America to persist in nature. In virology, this ecological dependence is important because it places natural limits on how far and how easily the virus can spread geographically.

This is one of the key scientific differences that is often overlooked when people compare every new outbreak to Covid-19.

The Andes virus is unusual among hantaviruses because human-to-human transmission has been documented before. However, available evidence suggests that such transmission is relatively rare and usually involves prolonged close contact, often within households or among family members. It does not spread with the same efficiency seen during the early stages of the Covid-19 pandemic, when brief encounters in enclosed spaces or public transport could lead to widespread transmission.

In simple terms, the Andes virus does not possess the same biological “engine” for rapid community spread.

Another important difference lies in its genetic behaviour. One of the major challenges during the Covid-19 pandemic was the rapid evolution of the coronavirus through mutations, producing successive variants within relatively short periods. Hantaviruses, including the Andes virus, are generally more genetically stable. From a public health standpoint, this is reassuring because it allows scientists and health authorities to predict viral behaviour more reliably and maintain the effectiveness of existing diagnostic tools for longer periods.

This does not mean the virus should be dismissed lightly.

Individuals infected with the Andes virus can develop Hantavirus Pulmonary Syndrome (HPS), a serious illness affecting the lungs and cardiovascular system. Early symptoms often resemble common viral infections, including fever, muscle aches, headaches, and fatigue, before progressing in some cases to breathing difficulties and severe respiratory complications.

But there is an important difference between a virus that can cause severe illness in individuals and one capable of overwhelming healthcare systems through explosive transmission.

Covid-19 became a global crisis not only because it could cause death, but because it spread extraordinarily quickly across populations. Hospitals around the world faced sudden surges of patients within short periods, placing healthcare systems under immense strain. At present, there is no strong evidence suggesting the Andes virus has the same capacity for widespread uncontrolled transmission.

Ecology also matters more than many people realise.

The rodent species most closely associated with the Andes virus does not exist in Malaysia. This significantly reduces the likelihood of natural transmission occurring locally. In infectious disease science, understanding the relationship between a virus and its natural host is often just as important as monitoring the number of reported cases.

For this reason, the current risk assessments by organisations such as the World Health Organization and the Centers for Disease Control and Prevention, which continue to classify the global threat level as low, remain consistent with the available scientific evidence.

Perhaps the more important lesson from situations like this is not about fear, but perspective.

The Covid-19 pandemic taught societies to take infectious diseases seriously, and that awareness remains valuable. But it also left many people emotionally conditioned to interpret every new outbreak through the lens of 2020. In reality, viruses differ greatly in how they spread, mutate, and sustain themselves within populations.

Public awareness is important. Panic is not.

As global disease surveillance becomes more advanced, reports of emerging viruses will likely become more common, not necessarily because the world is becoming more dangerous, but because we are now far better at detecting and monitoring outbreaks than before.

Understanding those differences calmly and scientifically may be one of the most important lessons we carry forward from the pandemic years.