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.

Made from fermented apples and naturally high in acetic acid, apple cider vinegar has been popular in recent years for its purported health benefits – from antibacterial properties to antioxidant effects and potential for helping manage blood sugars.

Its origins as a health tonic stretch much further back. Hippocrates used it to treat wounds, fever and skin sores.

An experimental study, released today, looks into whether apple cider vinegar could be effective for weight loss, reduce blood glucose levels and reduce blood lipids (cholesterol and triglycerides).

The results suggest it could reduce all three – but it might not be as simple as downing an apple cider vinegar drink a day.

What did they do?

A group of scientists in Lebanon did a double-blinded, randomised, clinical trial in a group of overweight and obese young people aged from 12–25 years.

Researchers randomly placed 30 participants in one of four groups. The participants were instructed to consume either 5, 10 or 15ml of apple cider vinegar diluted into 250ml of water each morning before they ate anything for 12 weeks. A control group consumed an inactive drink (a placebo) made (from lactic acid added to water) to look and taste the same.

Typically this sort of study provides high quality evidence as it can show cause and effect – that is the intervention (apple cider vinegar in this case) leads to a certain outcome. The study was also double-blinded, which means neither the participants or the scientists involved with collecting the data knew who was in which group.

So, what did they find?

After a period of three months apple cider vinegar consumption was linked with significant falls in body weight and body mass index (BMI). On average, those who drank apple cider vinegar during that period lost 6–8kg in weight and reduced their BMI by 2.7–3 points, depending on the dose. They also showed significant decreases in the waist and hip circumference.

The authors also report significant decreases in levels of blood glucose, triglycerides, and cholesterol in the apple cider groups. This finding echoes previous studies. The placebo group, who were given water with lactic acid, had much smaller decreases in weight and BMI. There were also no significant decreases in blood glucose and blood lipids.

From animal studies, it is thought the acetic acid in apple cider vinegar may affect the expression of genes involved in burning fats for energy. The new study did not explore whether this mechanism was involved in any weight loss.

Is this good news?

While the study appears promising, there are also reasons for caution.

Firstly, study participants were aged from 12 to 25, so we can’t say whether the results could apply to everyone.

The statistical methods used in the study don’t allow us to confidently say the same amount of weight loss would occur again if the study was done again.

And while the researchers kept records of the participants’ diet and exercise during the study, these were not published in the paper. This makes it difficult to determine if diet or exercise may have had an impact. We don’t know whether participants changed the amount they ate or the types of food they ate, or whether they changed their exercise levels.

The study used a placebo which they tried to make identical in appearance and taste to the active treatment. But people may still be able to determine differences. Researchers may ask participants at the end of a study to guess which group they were in to test the integrity of the placebo. Unfortunately this was not done in this study, so we can’t be certain if the participants knew or not.

Finally, the authors do not report whether anyone dropped out of the study. This could be important and influence results if people who did not lose weight quit due to lack of motivation.

Any other concerns?

Apple cider vinegar is acidic and there are concerns it may erode tooth enamel. This can be a problem with any acidic beverages, including fizzy drinks, lemon water and orange juice.

To minimise the risk of acid erosion some dentists recommend the following after drinking acidic drinks:

• rinsing out your mouth with tap water afterwards
• chewing sugar-free gum afterwards to stimulate saliva production
• avoiding brushing your teeth immediately after drinking because it might damage the teeth’s softened top layer
• drink with a straw to minimise contact with the teeth.

Down the hatch?

This study provides us with some evidence of a link between apple cider vinegar and weight loss. But before health professionals can recommend this as a weight loss strategy we need bigger and better conducted studies across a wider age range.

Such research would need to be done alongside a controlled background diet and exercise across all the participants. This would provide more robust evidence that apple cider vinegar could be a useful aid for weight loss.

Still, if you don’t mind the taste of apple cider vinegar then you could try drinking some for weight loss, alongside a healthy balanced and varied dietary intake. This study does not suggest people can eat whatever they like and drink apple cider vinegar as a way to control weight.

Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, Accredited Practising Dietitian, University of South Australia

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