COVID-19: What you need to know about the coronavirus pandemic on 29 June

Confirmed cases of COVID-19 have passed 181.4 million globally, according to Johns Hopkins University. The number of confirmed deaths stands at more than 3.92 million. More than 2.96 billion vaccination doses have been administered globally, according to Our World in Data.

Perth and Brisbane have joined Sydney and Darwin in introducing lockdowns in an Australia-wide effort to tackle an outbreak of COVID-19 cases.

Indonesia's government will wait until a significant fall in COVID-19 cases before re-opening Bali to foreign tourists, the country's tourism minister said in an interview yesterday.

It comes as the Red Cross warns that Indonesia's COVID-19 surge is on the brink of 'catastrophe'.

Restrictions have been extended in the Philippines until at least the middle of next month.

Health officials in Los Angeles county have recommended everyone wear masks indoors - regardless of vaccination status - because of the increased prevalence of the Delta variant.

Vietnam has approved Moderna's COVID-19 vaccine for emergency use. It's the 5th vaccine to be given such approval in the country.

The United States said yesterday it will donate 1 million shots of the Pfizer/BioNTech vaccine to Paraguay.

Spanish authorities have tightened rules for British tourists, with a negative COVID-19 test or proof of vaccination now required for entry. They'd been allowed in freely for more than a month.

Chilean President Sebastián Piñera has announced a $2 billion boost to health spending to tackle the COVID-19 pandemic.

A new study has shown that mixed two-dose schedules of the Pfizer/BioNtech and Oxford/AstraZeneca jabs produced high concentrations of antibodies.

The Oxford University study found that the mixed schedule was effective in any combination - i.e. AstraZeneca first, followed by Pfizer or vice versa. However, Reuters reports that a Pfizer shot given four weeks after an AstraZeneca shot produced better immune responses than another dose of AstraZeneca.

Professor Matthew Snape, who led the trial, said the findings could give flexibility to vaccine rollouts where supplies are uncertain. However, it wasn't large enough to recommend a broader shift anyway from current clinically-approved approaches.

"It's certainly encouraging that these antibody and T-cell responses look good with the mixed schedules," he told reporters.

"But I think your default has to stay, unless there's a very good reason otherwise, to what is proven to work," he added referring to the same-shot vaccine schedules assessed in clinical trials.

In another Oxford University study, researchers found that a third shot of the Oxford/AstraZeneca vaccine produces a strong immune response. However, scientists behind the research added that there was no evidence that such shots were needed, especially in light of global vaccine shortages.

The study found that a third dose increased antibody and T-cell immune responses, while the second dose could be delayed by up to 45 weeks and still lead to an enhanced immune response.

Andrew Pollard, director of the Oxford Vaccine Group, said that evidence that the vaccine protects against current variants for a sustained period of time meant that such a booster may not be needed.

"We do have to be in a position where we could boost if it turned out that was necessary ... (but) we don't have any evidence that that is required," he told reporters.

3. High-grade masks offer much better COVID-19 protection

Research from Cambridge University Hospital's NHS Foundation Trust has shown that the quality of face masks given to healthcare workers can make a massive difference to their risk of getting infected with COVID-19.

Wearing a high-grade mask - known as an FFP3 - can provide up to 100% protection. But, standard-issue surgical masks carry with them a much greater risk of catching COVID-19.

The results have been published in a pre-print paper and are not yet peer-reviewed, however.