Mexico City officials will begin offering a third Covid-19 vaccine dose to residents over the age of 60 as part of a government plan to roll out booster shots, Reuters reports.

President Andres Manuel Lopez Obrador said last week the third doses would be made available as soon as possible, beginning with elderly people who are more vulnerable to the coronavirus.

The first booster shots in the massive capital of nearly 10 million people will be AstraZeneca doses given to residents of the southern Tlalpan neighbourhood, officials told a news conference.

Islamabad, Gilgit-Baltistan and Azad Jammu and Kashmir have collectively reported 32 new Covid-19 infections in the last 24 hours.

The breakdown of cases is as follows:

• Islamabad: 30
• GB: 1
• AJK: 1

The capital also reported one more death from the coronavirus.

Punjab has detected 41 new coronavirus cases in the last 24 hours, taking its total infections to 443,560.

Moreover, the province also confirmed two more deaths, increasing its total fatalities to 13,042.

Khyber Pakhtunkhwa has reported 29 new coronavirus cases in the last 24 hours, down from 67 a day earlier, and two more deaths compared to four yesterday.

The province's tally of infections has risen to 180,412 while its death toll has reached 5,864.

Meanwhile, Balochistan has confirmed two more cases and deaths, taking its tally of infections to 33,509 and fatalities to 362.

The government's Covid-19 portal shows that 319 more people have recovered from the coronavirus in Pakistan, taking the country's total to 1,246,783.

There are 11,826 active virus patients in Pakistan, of whom 813 are in critical condition.

New York City has expanded its array of Covid-19 mandates, setting vaccine requirements for children as young as five years old and for workers at all private-sector companies as the highly transmissible Omicron variant pushes into more US states, Reuters reports.

The most-populous US city set a December 27 deadline for all 184,000 businesses within its limits to make their employees show proof they have been vaccinated, Mayor Bill de Blasio said.

In addition, children five to 11 years old must get at least one dose by Dec 14 and those 12 and older need to be fully vaccinated by Dec 27 to enter restaurants and participate in extracurricular school activities, such as sports, band and dances.

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The World Health Organisation (WHO) has said Covid treatments using plasma taken from the blood of recovered coronavirus patients should not be given to people with mild or moderate illness, AFP reports.

Convalescent plasma showed some early promise when given intravenously to people sick with Covid-19. But in advice published in the British Medical Journal, the WHO now says that “current evidence shows that it does not improve survival nor reduce the need for mechanical ventilation, and it is costly and time-consuming to administer”.

It made a “strong recommendation” against the use of blood plasma in people who do not have serious Covid-19 symptoms and said that even for patients with severe and critical illness, the treatment should only be given as part of a clinical trial.

A major British study into mixing Covid-19 vaccines has found that people had a better immune response when they received a first dose of AstraZeneca or Pfizer-BioNTech shots followed by Moderna nine weeks later, according to the results of the study.

"We found a really good immune response across the board ... in fact, higher than the threshold set by Oxford-AstraZeneca vaccine two doses," Matthew Snape, the Oxford professor behind the trial dubbed Com-COV2, told Reuters.

The findings supporting flexible dosing will offer some hope to poor and middle-income countries which may need to combine different brands between first and second shots if supplies run low or become unstable.

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