Beyond the media frenzy

There has been a media frenzy bordering on hysteria since we first wrote about the hantavirus outbreak on a cruise ship in the Atlantic. Hopefully this will be turned down over the next 2 weeks.

Trust in WHO and evidence-based medicine

It is important to point out these are real people caught in a life and death situation. The public health implications are important and it's comforting to know that the World Health Organisation (WHO) has become involved at an early stage.

Some may see WHO as a highly political organization and it's not always possible to distance politics from public health medicine. I believe WHO does operate on evidence-based medicine and this is important in this outbreak. Many of the negative outcomes of the COVID-19 pandemic were the result of local politics interfering with good evidence-based public health medicine.

Why this outbreak made headlines

Exotic infectious disease outbreaks are frequently reported. Ebola virus disease, Lassa fever and Marburg virus outbreaks have all been notified over the past 12 months. They receive some attention but generally are overlooked by the mainstream media. What makes this different is the fact it could have happened to us! It could have been any of us on this upmarket cruise to Antarctica. This brings it closer to home and makes it newsworthy.

Lessons from Argentina's 2018 outbreak

The media are unlikely to highlight the fact that Argentinian public health professionals were able to curb a significant outbreak of hantavirus in Chubut province in 2018. Thirty-four people were infected in the outbreak and there were eleven deaths. Superspreaders were identified as contributing to the outbreak initially. It was contained through meticulous contact tracing and the self-isolation of symptomatic individuals. This is good public health practice. Well done, Argentina.

Does this outbreak have pandemic potential?

Should we be concerned about this outbreak of hantavirus having pandemic potential? The answer is clearly no. In the above study the reproduction rate was initially believed to be above 2. It was later revised down to less than 1. The reproduction rate for a particular disease is the average number of people infected by a single case. For influenza the basic reproduction rate is between 1 and 2 and for COVID-19 it is between 2.5 and 3.5. The R number for measles is between 12 and 18. The level of immunity within a population determines the level of transmission. It can have a major impact on the reproduction rate.

Our concern should be for the individuals affected by this outbreak and whether they will have easy access to good quality health care. It should not be about a global pandemic. While there is no specific treatment for the disease, it appears that survival rates are high with good quality supportive care.

What happens next

We already know a great deal about hantavirus and more insight (evidence for the future) will be gained through this outbreak.

It is my impression that everyone on the cruise can be identified in the first instance. All will be investigated for possible exposure. This includes those who have already left the ship. Public health officials will be seeking information on any early symptoms of the disease, exposure risk and their possible contacts, particularly the first responders in medical facilities.

Contact tracing will involve many jurisdictions, including Australia, and most countries will have the resources of a high-income country. It is likely all foreign nationals will be returned (charter flights) to their country of origin under quarantine conditions.

The incubation period of the disease allows for identification of those at high risk for the disease and quarantine for all. It should be contained quite quickly.

If not, then there may be other factors operating. I'm sure we will have renowned experts talking about the possibility of mutations making it more infectious in due course. This hype in reporting is inevitable.

I put my faith in WHO and look forward to their experts providing situation reports.

At the same time Argentina will be looking for the source of the outbreak to make sure it doesn't become an epicentre for further outbreaks. This should not be forgotten.

This is a follow-up opinion piece. For the original news report on the cruise ship hantavirus outbreak, see Another strange case of hantavirus on a cruise ship: don't jump to conclusions.