The World Health Organization's chief scientist said Tuesday she was looking forward to the "second generation" of Covid-19 vaccines, which could include nasal sprays and oral versions.

Soumya Swaminathan said such vaccines could have advantages over the current crop as they would be easier to deliver than injections and could even be self-administered.

Swaminathan said there were 129 different candidate vaccines that have got as far as clinical trials -- being tested on humans -- while a further 194 are not yet that advanced in their development and are still being worked on in laboratories.

"This covers the entire range of technologies," she told a live interaction on WHO social media channels.

"They're still in development. I'm sure some of them will prove to be very safe and efficacious and others may not.

"There could be advantages to some of the second generation vaccines... clearly if you have an oral vaccine or an intra-nasal vaccine this is easier to deliver than an injectable.

"Ultimately we'll be able to choose the ones that are most appropriate.

"If not for Covid, we're going to use these platforms for other infections in the future."

Swaminathan explained the advantages of a vaccine being sprayed into the nose, as happens in some countries with influenza vaccines.

"If there's a local immune response then it will take care of the virus before it even goes and establishes itself in the lungs and starts causing a problem," she said.

The WHO has only given emergency use authorisation to seven Covid-19 vaccines: those created by Pfizer/BioNTech, Moderna, AstraZeneca, Johnson & Johnson, Sinopharm, Sinovac and last week Bharat Biotech.

"None of the vaccines are 100 percent. Nobody has ever claimed that the vaccines are going to be 100 percent protective. But 90 percent is a wonderful amount of protection to have, compared to zero," Swaminathan said.

"Till now, with the vaccines that we have approved, there has not been any signal which has been so worrying that we need to say, well, we need to re-think this vaccine."

More than 7.25 billion vaccine doses have been administered around the world, according to an AFP count.

Pfizer request

Drugmakers Pfizer and BioNTech announced Tuesday they have formally submitted a request asking US officials for emergency authorization of their Covid-19 booster vaccine for people aged 18 and older.

The move follows research published by the companies in late October indicating a third shot is 95.6 percent effective against symptomatic infection, based on clinical trials carried out on 10,000 people.

The companies asked the US Food and Drug Administration to add the new population segment, amending emergency use authorization already granted in September for a third dose for everyone aged 65 and up, as well as people at high risk of developing severe Covid-19.

Pfizer's initial proposal for approval of boosters to everyone aged 16 and over, which was backed by President Joe Biden's administration, was rejected at that time.

Several countries have already approved Covid-19 booster shots to increase immunity in people who have already been vaccinated, but whose protection may have dipped after several months, per some studies.

The European Medicines Agency (EMA) approved a booster for over-18s at the beginning of October, allowing national regulators to decide which groups should be eligible first.

France's over-65s will need booster for Covid pass: Macron

People over 65 in France will need to show proof of a Covid-19 booster jab to be able to visit restaurants, attend cultural events and take intercity trains, President Emmanuel Macron said Tuesday.

The pass has become a routine part of life for many people in France since August, with a complete course of vaccinations generating a QR code that is shown on entry to gain access to venues.

"From December 15, you (over-65s) will need to provide proof of a booster jab to extend the validity of your health pass," Macron said in an address to the nation warning that Covid-19 infection rates are climbing again in France.

Due to the rebound, masks will also again be compulsory for all students at elementary schools from next Monday, the education ministry announced after Macron's speech.

The new rule for over-65s will further tighten what is one of the strictest such regimes in Europe. There were protests in France when the measures were first introduced over the summer but they have since diminished.

"We have not finished with the pandemic," Macron said, explaining that while France is currently in a better position than either Germany or the UK, infection rates have gone up 40 percent over the past week.

Macron noted that "all the studies show" that six months after getting the vaccine, "immunity decreases and therefore the risk of developing a serious form (of Covid) increases".

"The solution to this decrease in immunity is an additional vaccine shot," he said.

- 'Responsible and united' -
Macron also urged the six million people eligible for the vaccine in France who have not yet even received a first dose to come forward and get the jab.

"This is an appeal to responsibility -- get vaccinated," he said.

Macron said more than 80 percent of the people in intensive care in France with Covid were aged over 50 and announced the government would launch a campaign in December for 50-64-year-olds to have booster shots.

He said that the booster campaign for the over 65s now had to be "accelerated".

The president appears eager to make a successful fight against coronavirus one of his key boasts in April presidential elections, where he is expected to stand for a second term even though he has yet to declare his candidacy.

Many analysts had warned he would face stiff opposition to the Covid pass plan in the summer but the strategy helped force a significant surge in vaccine take-up.

"To be free in a nation like France means being responsible and united. So I'm counting on you," Macron said.

The French leader added that the "vaccine alone is not enough" and mask-wearing rules needed to stay in place.

"Any relaxations that have been considered will be put off in order to keep the rules currently in force," he said.

Health pass checks will also be stepped up, he added.

Macron said France was "one of the most protected countries in the world" due to its vaccine rollout but warned that "we will have to live with this virus until the whole global population is immunised."