There is widespread concern over the emergence of new Covid-19 mutations as infection rates are ticking up globally again, with the highly transmissible Delta variant taking hold - especially among the unvaccinated - and in regions where anti-virus measures have been relaxed.

Ireland is one of the most vaccinated nations in the world with close to 90% of the adult population now having got at least one jab against the coronavirus.

Despite constant public service announcements and messages about the benefits of being inoculated there are still people who are vaccine hesitant if not completely vaccine resistant.

Research carried out into Covid-19 vaccine hesitancy and resistance in Ireland and the UK, published in January by Nature Communications, suggests that overall 65% of Irish respondents were accepting of a Covid-19 vaccine, 26% were hesitant, and 9% were resistant.

In comparison, 69% of UK respondents were vaccine accepting, 25% were vaccine hesitant, and 6% were vaccine resistant. Northern Ireland had the lowest rate of vaccine acceptance at 51%.

Dr Philip Hyland, Senior Lecturer at the Department of Psychology at Maynooth University, says the research showed that in Ireland, those who were hesitant about taking a Covid-19 vaccine were more likely to be female; a younger age (35-44); less altruistic; more likely to hold irrational beliefs (endorse religious and conspiratorial beliefs); lack trust in authority (lack trust in government, scientists, doctors/healthcare professionals); hold anti-migrant attitudes, and believe that one's own social group is superior to other groups in society.

He says that the best data available suggests that about 5-10% of people in the general population oppose vaccination of any kind.

Vaccine hesitance refers to the situation where people delay or consider not taking a vaccine, Prof Hyland explains, and anti-vaccination (or vaccine resistance) is where people positively oppose vaccination.

The former usually have concerns about vaccination that can be allayed through information while the latter usually have an ideological opposition to vaccination, he said.

In the US around 18% of adults are said to be vaccine resistant, according to a recent Gallup poll.

When asked, respondents said they are unlikely to change their mind about getting the vaccination. The percentage with this view has not changed in recent months.

The Center for Disease Control (CDC) reported that as of 31 August 74.2% of adults in the US had received at least one Covid-19 vaccine dose and 370.2 million doses having been administered since December 2020.

The adult population in the US is around 209 million, this leaves at least 38 million adults who have not yet been vaccinated at all.

The US had a huge surge in vaccinations earlier in the year with more than 4.4 million doses being given out in one day alone, on 8 April. But since then, the numbers being vaccinated has slowed.

The CDC reports that nationally, new admissions of patients with confirmed Covid-19 are currently at their highest levels since the start of the pandemic for all age groups under 50 years old.

Despite there having been more than 631,440 Covid-19 deaths reported in the United States, and around 142,000 new cases of the virus daily there are still many people determined not to get a vaccination.

Professor Afton Kapuscinski, director of the Psychological Services Center at Syracuse University in New York, explains that vaccine hesitancy has been with us from the moment the first vaccines, such as for smallpox, became widely available.

"However, data suggests hesitancy has varied over time, and has unfortunately increased in recent years. One indicator of the amplified hesitancy is the number of exemptions parents are seeking (and granted) for immunisations that are mandatory for children to attend school" in the US.

Prof Kapuscinski said people who are hesitant about vaccination are concerned about safety of the vaccine and are less likely to believe Covid poses a serious threat.

Some also cite distrust of media sources, health organisations, like the CDC, and government messaging but fear of needles and blood is also a factor, she said.

Younger adults who are politically conservative, those who are rural based and from lower socioeconomic groups are more likely to be vaccine hesitant, according to Prof Kapuscinski.

While there is also significant vaccine hesitancy among black Americans, which is declining, indigenous people in the United States have the highest vaccine rates of any racial group, Prof Kapunscinski said.

This has been explained by community leaders as being due to a strong emphasis on collectivist values -"the conviction that personal choices should consider what is best for the group. In this view, choosing to be vaccinated shows care for not only people important to you, but also other people’s friends, neighbours and grandmothers."

An Italian expert says the "anti-vaxxer" label is an umbrella term, which gives no space for the diversity of anti-vaccination sentiment.

Individuals may reject some vaccines but not others, they may have experienced adverse effects from prior vaccination and may reject vaccines for entirely political reasons, or use the rejection of vaccination to symbolise something else, Dr Serena Barello, Assistant Psychology Professor at Universitá Cattolica del Sacro Cuore in Milan, said.

The "anti-vaxxer" label puts all vaccine refusal into a fixed, static opposition to vaccination - even though most who decline vaccines are more accurately described as being hesitant towards them, she explains.

Dr Barello says that those who are vaccine hesitant have many reasons for not getting a jab such as issues of confidence - not trusting in vaccines or health care providers, complacency - not perceiving a need for vaccination or not valuing vaccination, and convenience - access or lack of to vaccination.

Both Prof Kapuscinski and Dr Barello say there has been a surge of emotionally charged discussions about vaccine hesitancy.

"For sure this phenomenon has become an issue of debate much more than in the past because we are talking about a global phenomenon that touches every country of our planet at the same time with health, social, economic and political huge effects," Dr Barello commented.

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Prof Kapuscinski points out that people who are vaccine hesitant, not specific to Covid-19 jabs, are more likely to have concerns about the government moving toward excessive control of individual freedoms.

"Some may see strong advocacy for vaccines or mandating vaccines for government workers as moving toward socialism," she said.

For some, there is a strong reaction to any perceived infringement on personal choices, she added.

"Nevertheless, I think it is a mistake to place too much emphasis on particular political ideologies or stereotypes of people who are vaccine hesitant.

"Most people who consider themselves to be conservative politically are not vaccine hesitant, so this may unnecessarily add to political polarisation.

"Additionally, a focus on political ideology is not productive in addressing the underlying reasons most people give for being unsure - namely, concerns about safety and necessity of the vaccine," she said.

Prof Hyland concurs that lack of trust in authorities and institutions is a defining feature of those who are vaccine resistant.

But, he said, his research during the pandemic suggests that most people who would have been classified as 'vaccine hesitant’ about the Covid-19 vaccine prior to its arrival ended up taking the vaccine when it was offered to them.

"The development of the Covid-19 vaccines is among the greatest scientific achievements of all time and the Irish public have overwhelmingly and enthusiastically embraced them, according to Prof Hyland.

He said there seems to be no question that those who are ‘hesitant’ can be moved toward an accepting position with clear, scientific information.

Prof Kapuscinski said that "while there are personality characteristics, like reactance, that make someone more likely to be hesitant, many people are truly on the fence and interested in new information about vaccine safety and the risks of Covid.

"What tends to get most of us to dig our heels in harder is argumentative, hostile or guilt-inducing messaging," she said.

"When having a discussion with someone who is hesitant, it is not likely that lecturing, arguing, or even presenting ‘facts’ to combat misinformation at the outset of the conversation is likely to be effective.

"In fact, it would probably backfire.

"People also do not feel safe to have an open discussion when they feel like they are being pressured or criticised," she said.

Prof Hyland believes people with anti-vaccine attitudes cannot be reasoned out of their views. He says "their position is a faith-based belief system".

They "hold a rigid belief and engage in motivated reasoning" to dismiss all evidence or reason contrary to their belief, "focus selectively on information that supports their belief", and "distort information so that it fits with their belief", he said.

"We would not make accommodations for people who believe the world is flat, and I don’t think we should make any accommodations for people who believe vaccines are unsafe and refuse to take them during a global pandemic where millions of people are suffering and dying," Prof Hyland said.

He concludes that while the influence of religion and religious groups is still strong in Ireland, it is waning and there has been little in the way of a widespread and concerted effort to instill fear of vaccination in the public or to derail the vaccination programme here.

What the pandemic and the vaccine roll-out seem to have shown is that Irish society is very robust to threats that can lead to "cracks" and distrust that can exist between groups and the Government and national institutions, he said.

Dr Barello said it is important to recognise that hesitant individuals encompass a wide range of people who differ from the very small percentage who totally refuse all vaccinations and have no doubts about doing this.

She said that acceptance of vaccination is an "outcome behavior" resulting from a complex decision-making process that can be potentially influenced by a wide range of factors.

"Unlike with the social determinants of health, vaccine hesitancy determinants like education and socio-economic status do not necessarily influence hesitancy in only one direction.

"It is interesting that in many studies, higher education may be associated with both lower and higher levels of vaccine acceptance," Dr Barello said.

The role of scientists in the public eye is silently, yet dramatically changing, she says, with decision-makers asking research experts to provide evidence on which political acts should be grounded.

Dr Barello said that media coverage of the pandemic features a daily presence of scientists and public health professionals on the television and on the web, highlighting the key role of experts to deal with the emergency, but making also clear that any solution is still far from being conclusive.

It is increasingly becoming evident that the time needed for public health and scientific advance exceeds the time expected by citizens to obtain satisfactory responses, she said.

"In a way, science is slow, uncertain, discordant, and fragile; and the increasing public awareness of its probabilistic nature may change the public perception of scientific knowledge for a long time.

"Lessons learned from previous epidemics suggest that disasters can affect the public understanding of science and the citizens' trust in scientists and experts.

"As for the Covid-19 emergency, a recent Italian study suggests that while an initial increase in attention and information-seeking from scientists was registered on social media in February - the very start of the epidemic in Italy -, a dramatic decline in trust toward scientific and health authorities occurred in March 2020.

As a result, the unprecedented and massive exposure of science to the public, together with the lack of definitive responses to citizens' needs, risks a dramatic loss of trust in science.

Prof Hyland says that he has no doubt that public communications by people like Professor Luke O’Neill (Professor of Biochemistry in the School of Biochemistry and Immunology at Trinity College Dublin) throughout the pandemic "have been invaluable in moving many people who were hesitant about taking the Covid-19 vaccine to an accepting position.

"I don’t think his role in the public communication of science during this time can be underestimated," he said.

However, the WHO has said low vaccination uptake in priority populations in a number of European countries is still very concerning.

The WHO’s Europe Director, Hans Kluge, said high transmission rates across the continent were "deeply worrying, particularly in the light of low vaccination uptake in priority populations in a number of countries."

Speaking earlier this week, Mr Kluge said the Delta variant was partly to blame, along with an "exaggerated easing" of restrictions and measures and a surge in summer travel.

While around half of people in Europe are fully vaccinated, uptake has slowed despite around 1.3 million Covid deaths to date in the region.

"In the past six weeks, it has fallen by 14%, influenced by a lack of access to vaccines in some countries and a lack of vaccine acceptance in others."

Only 6% of people in lower and lower-middle income countries in Europe are fully vaccinated, and some countries have only managed to vaccinate one in 10 health professionals.

Mr Kluge stressed that since anti-Covid measures were being relaxed in many places, "the public's vaccination acceptance is crucial".

"Vaccine scepticism and science denial is holding us back from stabilising this crisis. It serves no purpose, and is good for no one", he said.

Dr Philip Hyland is a Senior Lecturer at the Department of Psychology, Maynooth University.

Afton Kapuscinski is director of the Psychological Services Center at Syracuse University and an assistant teaching professor of psychology.

Dr Serena Barello is Assistant Professor of Consumer and Health Psychology, EngageMinds HUB - Consumer, Food and Health Engagement Research center at Universitá Cattolica del Sacro Cuore in Milan.

Additional reporting: Reuters/AFP