I forgot about the disease. tetanus and diphtheria are included. There is a vaccine for polio. The global drive to suppress some of the biggest killers in history has fallen back in the race to vaccine the world against Covid-19.

Even though the global distribution has been different, almost 12n doses of Covid-19 vaccine have been administered in less than 18 months. More than 30 million children missed out on other vaccinations during the Pandemic, with south-east Asia and the eastern Mediterranean region being the worst hit. Many young people will be at risk of diseases such as tetanus, diphtheria, and pertussis, which kill tens of thousands of people every year.

Clinics closing and staff being diverted are some of the reasons for the decline in routine vaccination. There are people who haven't accepted vaccines for themselves or their children when they've been offered them.

The challenge of building trust in vaccines has become more important as we enter World Immunization Week because of the dangerous dip in vaccination levels. The good news is that we now know how to increase vaccine use, and that the Pandemic has taught us some important lessons.

While the past few years have seen increased hostility towards those who refuse vaccines, lumping them together into a single group is not wise. Some people find the term offensive because they don't have questions or concerns about vaccines.

There is a spectrum of vaccine hesitancy. The hardliners who want to absorb attention but are not willing to change are at one end. Those whose views are not permanently fixed are at the other.

Prof Julie Leask made the case for engaging with those who can be won over in her landmark Nature paper, Target the Fence-Sitters. It's a waste of energy to insult hardliners, and they can end up nudging people in the wrong direction.

More than a decade on from that publication, research is mounting on why people don't vaccine. Some of this has been applied to good effect during the Covid-19 roll out.

The vaccine conversations have become more political during the Pandemic. Changing one's mind about vaccination is a problem that health authorities need to address. It doesn't feel good to do a U-turn. It becomes unconformable if you choose to vaccine because you are seen as a personal capitulation or political concession.

There is no one political grouping that has a monopoly on vaccines. In the US, right-leaning voters are less likely to bevaccinated than in the UK. The pursuit of purity is one of the reasons why vaccine misinformation is a growing source.

As vaccination is wrapped up in people's identity, attitudes can quickly change. It can make people feel as if they are betraying themselves or their tribe if they choose to bevaccinated. When someone opts out of one vaccine, they are more likely to opt out of others. The next flu vaccine might not be taken by those who refuse a Covid jab. Uncoupling vaccines from people's attitudes prevents them from rejecting them.

There are more practical steps that can be taken to improve vaccine take up. There is evidence that presumptive recommendations can increase acceptance, so instead of opening a debate on vaccines with every patient or parent, doctors might say, "It's time for Charlie." People who have questions would be engaging in greater depth.

Motivational interviewing, a time-consuming but effective way to inject a little empathy into doctor-patient conversations on vaccination, has shown promise in improving vaccination receptiveness by discussing individual drivers of scepticism.

Listening is a crucial skill. Doctors ask their patient to voice their concerns about vaccines in a non-judgmental way. Both parties are open to discussion, even though they may not see vaccines in the same way. The heat is out of a potential conflict and the door is open for a change of heart.

The WHO working group set out the 3Cs of vaccine hesitancy in a report. In the global south, easy access to free immunisation may be a bigger challenge, but convenience is often overlooked.

Asking people why they skip vaccines is the best way to find out. It may have been tempting to imagine a religious or philosophical objection to the vaccine when it was being used. Many parents with large families cited the hassle of taking their children on public transport as an obstacle. Service providers responded by scheduling clinics nearby on days that suited the community.

Complacency is important as well. To get herd immunity against the disease, you need to hit about 85%. The door to a resurgence can be opened once the virus is suppressed.

Confidence is hard won and easily lost. There are lessons that can be learned from how public trust in other vaccines has been restored.

A broad alliance of health professionals, teachers, parents, cancer societies and children's advocacy groups came together to show their support for the campaign when the rate of vaccine for the human immunodeficiency virus fell from 87% to 50% in 2015. A media campaign fronted by a high-profile cancer patient helped Ireland to arrest the decline.

To the credit of some health authorities, several Covid-19 immunisation campaigns have adopted personalised vaccine invitations and made vaccinations more convenient by allowing community pharmacists to offer the jab.

Most have avoided the kind of blunt myth- busting and debunking that can backfire, instead finding ways to apply science communication research and tackle misinformation in the real world. Facts alone are not enough to win people over.

Australia has developed decision aids to walk people through the pros and cons of signing up, the US has been quick to try mobile pop-up vaccine clinics, and Romania has offered jabs at popular tourist spots.

France has recorded stellar take-up of Covid-19 vaccinations despite being dubbed the unvaccinated country. If the incentives are right, even countries with vaccine scepticism can turn things around.

It is time to apply all of this with unprecedented energy to close the immunisation gaps that have arisen during the Pandemic. The goal should be to regain lost ground as quickly as possible, and then go the extra mile to reach those who have never received a vaccine dose.

  • Gary Finnegan is a health journalist.