We know vaccines have been a miracle for public health. Now, new research led by the World Health Organization has found vaccines have saved an estimated 154 million lives in the past 50 years from 14 different diseases. Most of these have been children under five, and around two-thirds children under one year old.

In 1974 the World Health Assembly launched the Expanded Programme on Immunization with the goal to vaccinate all children against diphtheria, tetanus, pertussis (whooping cough), measles, polio, tuberculosis and smallpox by 1990. The program was subsequently expanded to include several other diseases.

The modelling, marking 50 years since this program was established, shows a child aged under ten has about a 40% greater chance of living until their next birthday, compared to if we didn’t have vaccines. And these positive effects can be seen well into adult life. A 50-year-old has a 16% greater chance of celebrating their next birthday thanks to vaccines.

What the study did

The researchers developed mathematical and statistical models which took in vaccine coverage data and population numbers from 194 countries for the years 1974–2024. Not all diseases were included (for example smallpox, which was eradicated in 1980, was left out).

The analysis includes vaccines for 14 diseases, with 11 of these included in the Expanded Programme on Immunization. For some countries, additional vaccines such as Japanese encephalitis, meningitis A and yellow fever were included, as these diseases contribute to major disease burden in certain settings.

The models were used to simulate how diseases would have spread from 1974 to now, as vaccines were introduced, for each country and age group, incorporating data on increasing vaccine coverage over time.

Children are the greatest beneficiaries of vaccines

Since 1974, the rates of deaths in children before their first birthday has more than halved. The researchers calculated almost 40% of this reduction is due to vaccines.

The effects have been greatest for children born in the 1980s because of the intensive efforts made globally to reduce the burden of diseases like measles, polio and whooping cough.

Some 60% of the 154 million lives saved would have been lives lost to measles. This is likely due to its ability to spread rapidly. One person with measles can spread the infection to 12–18 people.

The study also found some variation across different parts of the world. For example, vaccination programs have had a much greater impact on the probability of children living longer across low- and middle-income countries and settings with weaker health systems such as the eastern Mediterranean and African regions. These results highlight the important role vaccines play in promoting health equity.

Vaccine success is not assured

Low or declining vaccine coverage can lead to epidemics which can devastate communities and overwhelm health systems.

Notably, the COVID pandemic saw an overall decline in measles vaccine coverage, with 86% of children having received their first dose in 2019 to 83% in 2022. This is concerning because very high levels of vaccination coverage (more than 95%) are required to achieve herd immunity against measles.

In Australia, the coverage for childhood vaccines, including measles, mumps and rubella, has declined compared to before the pandemic.

This study is a reminder of why we need to continue to vaccinate – not just against measles, but against all diseases we have safe and effective vaccines for.

The results of this research don’t tell us the full story about the impact of vaccines. For example, the authors didn’t include data for some vaccines such as COVID and HPV (human papillomavirus). Also, like with all modelling studies, there are some uncertainties, as data was not available for all time periods and countries.

Nonetheless, the results show the success of global vaccination programs over time. If we want to continue to see lives saved, we need to keep investing in vaccination locally, regionally and globally.

Meru Sheel, Associate Professor and Epidemiologist, Infectious Diseases, Immunisation and Emergencies Group, Sydney School of Public Health, University of Sydney and Alexandra Hogan, Mathematical epidemiologist, UNSW Sydney

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

Iron deficiency is common and can be debilitating. It mainly affects women. One in three premenopausal women are low in iron compared to just 5% of Australian men. Iron deficiency particularly affects teenage girls, women who do a lot of exercise and those who are pregnant.

The body needs iron to make new red blood cells, and to support energy production, the immune system and cognitive function. If you’re low, you may experience a range of symptoms including fatigue, weakness, shortness of breath, headache, irregular heartbeat and reduced concentration.

If a blood test shows you’re iron deficient, your doctor may recommend you start taking an oral iron supplement. But should you take a tablet or a liquid? With food or not? And when is the best time of day?

Here are some tips to help you work out how, when and what iron supplement to take.

How do I pick the right iron supplement?

The iron in your body is called “elemental iron”. Choosing the right oral supplement and dose will depend on how much elemental iron it has – your doctor will advise exactly how much you need.

The sweet spot is between 60-120 mg of elemental iron. Any less and the supplement won’t be effective in topping up your iron levels. Any higher and you risk gastrointestinal symptoms such as diarrhoea, cramping and stomach pain.

In Australia, iron salts are the most common oral supplements because they are cheap, effective and come in different delivery methods (tablets, capsules, liquid formulas). The iron salts you are most likely to find in your local chemist are ferrous sulfate (~20% elemental iron), ferrous gluconate (~12%) and ferrous fumarate (~33%).

These formulations all work similarly, so your choice should come down to dose and cost.

Many multivitamins may look like an iron supplement, but it’s important to note they usually have too little iron – usually less than 20 mg – to correct an iron deficiency.

Should I take tablets or liquid formulas?

Iron contained within a tablet is just as well absorbed as iron found in a liquid supplement. Choosing the right one usually comes down to personal preference.

The main difference is that liquid formulas tend to contain less iron than tablets. That means you might need to take more of the product to get the right dose, so using a liquid supplement could work out to be more expensive in the long term.

What should I eat with my iron supplement?

Research has shown you will absorb more of the iron in your supplement if you take it on an empty stomach. But this can cause more gastrointestinal issues, so might not be practical for everyone.

If you do take your supplement with meals, it’s important to think about what types of food will boost – rather than limit – iron absorption. For example, taking the supplement alongside vitamin C improves your body’s ability to absorb it.

Some supplements already contain vitamin C. Otherwise you could take the supplement along with a glass of orange juice, or other vitamin C-rich foods.

On the other hand, tea, coffee and calcium all decrease the body’s ability to absorb iron. So you should try to limit these close to the time you take your supplement.

Should I take my supplement in the morning or evening?

The best time of day to take your supplement is in the morning. The body can absorb significantly more iron earlier in the day, when concentrations of hepcidin (the main hormone that regulates iron) are at their lowest.

Exercise also affects the hormone that regulates iron. That means taking your iron supplement after exercising can limit your ability to absorb it. Taking your supplement in the hours following exercise will mean significantly poorer absorption, especially if you take it between two and five hours after you stop.

Our research has shown if you exercise every day, the best time to take your supplement is in the morning before training, or immediately after (within 30 minutes).

My supplements are upsetting my stomach. What should I do?

If you experience gastrointestinal side effects such as diarrhoea or cramps when you take iron supplements, you may want to consider taking your supplement every second day, rather than daily.

Taking a supplement every day is still the fastest way to restore your iron levels. But a recent study has shown taking the same total dose can be just as effective when it’s taken on alternate days. For example, taking a supplement every day for three months works as well as every second day for six months. This results in fewer side effects.

Oral iron supplements can be a cheap and easy way to correct an iron deficiency. But ensuring you are taking the right product, under the right conditions, is crucial for their success.

It’s also important to check your iron levels prior to commencing iron supplementation and do so only under medical advice. In large amounts, iron can be toxic, so you don’t want to be consuming additional iron if your body doesn’t need it.

If you think you may be low on iron, talk to your GP to find out your best options.

Alannah McKay, Postdoctoral Research Fellow, Sports Nutrition, Australian Catholic University

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