Half the world’s population has oral disease, plus other health stories you need to read this week

Nearly half of the world's population, or 3.5 billion people, suffers from oral diseases, the majority of them in low- and middle-income countries, the World Health Organization (WHO) has said.

The most common oral illnesses are tooth decay, severe gum disease, tooth loss and oral cancers, with untreated tooth decay affecting nearly 2.5 billion people, the United Nations agency said.

WHO cited large out-of-pocket expenditure and the unavailability of highly specialized dental equipment in primary healthcare facilities as two of the reasons for the high prevalence of oral diseases, especially in poor countries.

"Oral health has long been neglected in global health, but many oral diseases can be prevented," said WHO Director-General, Tedros Adhanom Ghebreyesus.

The agency suggested countries include equitable oral health services as part of their national planning and integrate oral health services into their primary health care models, Reuters reports.

Beijing shut parks, shopping malls and museums while more Chinese cities resumed mass testing for COVID-19, as China fights a spike in cases, deepening concerns about its economy and dampening hopes for a quick post-coronavirus reopening, Reuters reports.

China reported 28,127 new local cases nationally, nearing its daily peak from April, with infections in the southern city of Guangzhou and the southwestern municipality of Chongqing accounting for about half of the total.

In Beijing, cases are hitting fresh highs each day, prompting calls from the city's government for more residents to stay put.

City authorities said people arriving in the capital from elsewhere in China would need to undergo three days of COVID testing before they are permitted to leave their homes or accommodation.

There were two new deaths attributed to COVID-19 by health officials, compared with three over the weekend, which were China's first since May, Reuters adds.

The Netherlands is to cull another 29,000 chickens on a farm in the north of the country after the detection of a highly infectious strain of bird flu. Some 6 million birds have already been culled in the Netherlands since the new variant of the disease was first detected on 26 October last year, Reuters reports.

The recreational use of nitrous oxide, also known as ‘laughing gas’, is on the rise in Europe among young people, producing worrying numbers of poisonings, the European Union drugs monitoring agency EMCDDA has said in a study. In Denmark, cases of nitrous oxide poisoning have increased from 16 in 2015 to 73 last year; in France cases jumped to 134 in 2020 from 10 reported in 2017; while the Netherlands had 144 cases in 2020, Reuters reports.

Short intense exercise has been found to be more effective than slower, longer exercise, according to a new study. Researchers from the NIH Care Research Centre in Cambridge found that doing just two brisk walks for an hour and fifteen minutes a week or one run for the same amount of time a week is enough to lower heart disease risk, the Good News Network reports.

Blood that has been grown in a laboratory has been put into people in a world-first clinical trial, UK researchers say. Tiny amounts - equivalent to a couple of spoonfuls - are being tested to see how it performs inside the body, the BBC reports.

91% of parents say their family is less stressed when they eat together, according to a new survey from the American Heart Association, highlighting mealtime impact on mental well-being. 65% of surveyed adults said they are at least somewhat stressed, and more than a quarter (27%) are very or extremely stressed. Meanwhile, 84% of adults wish they could share a meal together more often, according to the research.

In the EU, the COVID-19 pandemic has seen a surge in superbug infections, according to a report by the European Centre for Disease Prevention and Control (ECDC). Some scientists link this rise in infections during the pandemic to wider antibiotic prescriptions given to treat COVID-19 and other bacterial infections during long hospital stays.

You are probably aware of the two main blood group systems: the AB system and the rhesus system. It may surprise you to hear, though, that there are more blood groups than you think – here’s why they matter.

What is inflammation? Two immunologists who study how the immune system reacts during infections, vaccination and autoimmune diseases explain.

The COVID-19 pandemic exposed the vulnerabilities of global and national health systems. As it appears to be in transition, now is the optimal moment to reflect on lessons learned.