Before the COVID pandemic, the World Health Organization (WHO) had made a list of priority infectious diseases. These were felt to pose a threat to international public health, but where research was still needed to improve their surveillance and diagnosis. In 2018, “disease X” was included, which signified that a pathogen previously not on our radar could cause a pandemic.

While it’s one thing to acknowledge the limits to our knowledge of the microbial soup we live in, more recent attention has focused on how we might systematically approach future pandemic risks.

Former US Secretary of Defense Donald Rumsfeld famously talked about “known knowns” (things we know we know), “known unknowns” (things we know we don’t know), and “unknown unknowns” (the things we don’t know we don’t know).

Although this may have been controversial in its original context of weapons of mass destruction, it provides a way to think about how we might approach future pandemic threats.

Influenza: a ‘known known’

Influenza is largely a known entity; we essentially have a minor pandemic every winter with small changes in the virus each year. But more major changes can also occur, resulting in spread through populations with little pre-existing immunity. We saw this most recently in 2009 with the swine flu pandemic.

However, there’s a lot we don’t understand about what drives influenza mutations, how these interact with population-level immunity, and how best to make predictions about transmission, severity and impact each year.

The current H5N1 subtype of avian influenza (“bird flu”) has spread widely around the world. It has led to the deaths of many millions of birds and spread to several mammalian species including cows in the United States and marine mammals in South America.

Human cases have been reported in people who have had close contact with infected animals, but fortunately there’s currently no sustained spread between people.

While detecting influenza in animals is a huge task in a large country such as Australia, there are systems in place to detect and respond to bird flu in wildlife and production animals.

It’s inevitable there will be more influenza pandemics in the future. But it isn’t always the one we are worried about.

Attention had been focused on avian influenza since 1997, when an outbreak in birds in Hong Kong caused severe disease in humans. But the subsequent pandemic in 2009 originated in pigs in central Mexico.

Coronaviruses: an ‘unknown known’

Although Rumsfeld didn’t talk about “unknown knowns”, coronaviruses would be appropriate for this category. We knew more about coronaviruses than most people might have thought before the COVID pandemic.

We’d had experience with severe acute respiratory syndrome (SARS) and Middle Eastern respiratory syndrome (MERS) causing large outbreaks. Both are caused by viruses closely related to SARS-CoV-2, the coronavirus that causes COVID. While these might have faded from public consciousness before COVID, coronaviruses were listed in the 2015 WHO list of diseases with pandemic potential.

Previous research into the earlier coronaviruses proved vital in allowing COVID vaccines to be developed rapidly. For example, the Oxford group’s initial work on a MERS vaccine was key to the development of AstraZeneca’s COVID vaccine.

Similarly, previous research into the structure of the spike protein – a protein on the surface of coronaviruses that allows it to attach to our cells – was helpful in developing mRNA vaccines for COVID.

It would seem likely there will be further coronavirus pandemics in the future. And even if they don’t occur at the scale of COVID, the impacts can be significant. For example, when MERS spread to South Korea in 2015, it only caused 186 cases over two months, but the cost of controlling it was estimated at US$8 billion (A$11.6 billion).

The 25 viral families: an approach to ‘known unknowns’

Attention has now turned to the known unknowns. There are about 120 viruses from 25 families that are known to cause human disease. Members of each viral family share common properties and our immune systems respond to them in similar ways.

An example is the flavivirus family, of which the best-known members are yellow fever virus and dengue fever virus. This family also includes several other important viruses, such as Zika virus (which can cause birth defects when pregnant women are infected) and West Nile virus (which causes encephalitis, or inflammation of the brain).

The WHO’s blueprint for epidemics aims to consider threats from different classes of viruses and bacteria. It looks at individual pathogens as examples from each category to expand our understanding systematically.

The US National Institute of Allergy and Infectious Diseases has taken this a step further, preparing vaccines and therapies for a list of prototype pathogens from key virus families. The goal is to be able to adapt this knowledge to new vaccines and treatments if a pandemic were to arise from a closely related virus.

Pathogen X, the ‘unknown unknown’

There are also the unknown unknowns, or “disease X” – an unknown pathogen with the potential to trigger a severe global epidemic. To prepare for this, we need to adopt new forms of surveillance specifically looking at where new pathogens could emerge.

In recent years, there’s been an increasing recognition that we need to take a broader view of health beyond only thinking about human health, but also animals and the environment. This concept is known as “One Health” and considers issues such as climate change, intensive agricultural practices, trade in exotic animals, increased human encroachment into wildlife habitats, changing international travel, and urbanisation.

This has implications not only for where to look for new infectious diseases, but also how we can reduce the risk of “spillover” from animals to humans. This might include targeted testing of animals and people who work closely with animals. Currently, testing is mainly directed towards known viruses, but new technologies can look for as yet unknown viruses in patients with symptoms consistent with new infections.

We live in a vast world of potential microbiological threats. While influenza and coronaviruses have a track record of causing past pandemics, a longer list of new pathogens could still cause outbreaks with significant consequences.

Continued surveillance for new pathogens, improving our understanding of important virus families, and developing policies to reduce the risk of spillover will all be important for reducing the risk of future pandemics.

This article is part of a series on the next pandemic.

Allen Cheng, Professor of Infectious Diseases, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Changes are coming into effect from February 1 about how paracetamol is sold in Australia.

This mainly affects pack sizes of paracetamol sold outside pharmacies and how paracetamol is accessed in pharmacies.

The changes, announced by Australia’s drug regulator, are in line with moves internationally to reduce the harms of liver toxicity and the risk of overdose.

However, there are no new safety concerns when paracetamol is used as directed. And children’s products are not affected.

What is paracetamol?

Paracetamol is commonly sold under brand names such as Panadol, Dymadon and Panamax. It’s used to treat mild pain and fever for short periods or can be prescribed for chronic (long-term) pain.

Millions of packs of this cheap and accessible medicine are sold in Australia every year.

Small packs (up to 20 tablets) have been available from supermarkets and other retailers such as petrol stations. Larger packs (up to 100 tablets) are only available from pharmacies.

Paracetamol is relatively safe when used as directed. However, at higher-than-recommended doses, it can cause liver toxicity. In severe cases and when left untreated, this can be lethal.

Why are the rules changing?

In 2022, we wrote about how the Therapeutic Goods Administration (TGA) was considering changes to paracetamol access because of an increase in people going to hospital with paracetamol poisoning.

An expert review it commissioned found there were about 40–50 deaths every year from paracetamol poisoning between 2007 and 2020. Between 2009–10 and 2016–17, hospital admissions for this increased (from 8,617 to 11,697), before reducing in 2019–20 (8,723). Most admissions were due to intentional self-poisonings, and about half of these were among people aged ten to 24.

After the report, the TGA consulted with the public to work out how to prevent paracetamol poisonings.

Options included reducing pack sizes, limiting how many packs could be bought at once, moving larger packs behind the pharmacy counter and restricting access by age.

Responses were mixed. Although responses supported the need to prevent poisonings, there were concerns about how changes might affect:

• people with chronic pain, especially those in regional areas, where it may be harder to access pharmacies and, therefore, larger packs
• people on limited incomes, if certain products were made prescription-only.

Although deaths from paracetamol poisoning are tragic and preventable, they are rare considering how much paracetamol Australians use. There is less than one death due to poisoning for every million packs sold.

Because of this, it was important the TGA addressed concerns about poisonings while making sure Australians still had easy access to this essential medicine.

So what’s changing?

The key changes being introduced relate to new rules about the pack sizes that can be sold outside pharmacies, and the location of products sold in pharmacies.

From February 1, packs sold in supermarkets and places other than pharmacies will reduce from a maximum 20 tablets to 16 tablets per pack. These changes bring Australia in line with other countries. These include the United Kingdom, which restricted supermarket packs to 16 tablets in 1998, and saw reductions in poisonings.

In all jurisdictions except Queensland and Western Australia, packs sold in pharmacies larger than 50 tablets will move behind the pharmacy counter and can only be sold under pharmacist supervision. In Queensland and WA, products containing more than 16 tablets will only be available from behind the pharmacy counter and sold under pharmacist supervision.

In all jurisdictions, any packs containing more than 50 tablets will need to be sold in blister packs, rather than bottles.

Several paracetamol products are not affected by these changes. These include children’s products, slow-release formulations (for example, “osteo” products), and products already behind the pharmacy counter or only available via prescription.

What else do I need to know?

These changes have been introduced to reduce the risk of poisonings from people exceeding recommended doses. The overall safety profile of paracetamol has not changed.

Paracetamol is still available from all current locations and there are no plans to make it prescription-only or remove it from supermarkets altogether. Many companies have already been updating their packaging to ensure there are no gaps in supply.

The reduction in pack sizes of paracetamol available in supermarkets means a pack of 16 tablets will now last two days instead of two-and-a-half days if taken at the maximum dose (two tablets, four times a day). Anyone in pain that does not improve after short-term use should speak to their pharmacist or GP.

For people who use paracetamol regularly for chronic pain, it is more cost-effective to continue buying larger packs from pharmacies. As larger packs (50+ tablets) need to be kept out of sight, you will need to ask at the pharmacy counter. Pharmacists know that for many people it’s appropriate to use paracetamol daily for chronic pain.

Natasa Gisev, Clinical pharmacist and Scientia Associate Professor at the National Drug and Alcohol Research Centre, UNSW Sydney and Ria Hopkins, Postdoctoral Research Fellow, National Drug and Alcohol Research Centre, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.