I think one point missed by most of the previous answers, is that vaccination has effectively had a history of being politically weaponised in the past, against many large groups.
People don't forget that, so there is a large underlying willingness to believe and be deeply suspicious.
While laws can coerce many things, there are limits to what can be demanded by law without invoking mass civic disobedience, and ending up with a worse situation than you would have had without it. A population has a general sense of what is perceived by it, as reasonable or unreasonable, and what enforcement is okay or not okay.
Causes of public suspicion
When you consider mass vaccination, you need to look at it in the context of things both real and fantastical, because this is emotion you're discussing:
The worldwide war on truth vs. truthiness, conspiracy theories, and sowing of distrust
- QAnon (look how many people were willing and eager to believe theories about satanic pedophiles, 9/11, and conspiracy theories generally)
- Bill Gates microchipping the world
- Some elite controlling everything for the last few thousand years
- Fake news claims
- The Big Lie
Politicians who themselves deny that COVID-19 matters
- USA (previously)
Reasonable fears by those ignorant of scientific and medical matters
- First mRNA style vaccines
- Concerns about genetic modification, tampering at the DNA level (most people wouldn't know the difference between DNA and RNA, and anyway, how do scientists know that it can't or won't modify in some way they hadn't thought of?)
- Previous medicines that have had serious effects down the line
- Mass use of an entirely new type of medicine (will it be forced on us? After only a few months testing?)
Widespread belief in other healing methods
- If people believe in magic, spiritual healing, or a "just world" run by deities, will they be more prone to see a pandemic as something that is by that deity's choice, and morally wrong to be interfered with by humanity? ("God sent AIDS to punish the gays for transgressing His law", COVID-19 has had similar claims too. If you see COVID-19 as Gods righteousness, what does that make vaccination?)
Abuse/weaponisation of vaccines previously
- People in some countries and cultures, may be unaware of this. But vaccine programs and vaccinations have been abused in the past. Tested in developing countries with poor results hidden, or used to trace, identify and hunt down persons of interest (Bin Laden in Pakistan, for example). People in many cultures and of many ethnic backgrounds do remember these and are deeply suspicious of vaccines as a result.
- More broadly, this is within a context of not-uncommon officially sanctioned medical abuse - think of women sterilised in some countries and programs, without being told that's what was going to happen, or other horrific examples that breached trust in the medical world.
- Consider even older established vaccines such as polio, were already being treated with suspicion and the disease eradication program outcomes over recent years.
Which means that....
With such a bunch of strong motives by so many, combined with all the other reasons (medical ethics/freedom of choice political beliefs, etc.) it becomes politically impossible to force vaccination on the world in most countries.
- Enough people would refuse to be complicit to make the delivery chain work (production, distribution, vaccination delivery staff, and doctors)
- Politicians, being vote and sentiment sensitive, would feel that to be an unreachable proposition, as a bottom line
- If approved and delivered, the backlash from the population would be immense. Rioting, civil disobedience and plain noncompliance/refusal.
- By the time vaccines have become available and tested, uptake is very high anyway and social perception acts to support further uptake (you can see your friends and neighbours doing it, so you're more likely to agree to do it)
- It may prove unnecessary to coerce, enough uptake may happen by peer pressure and exhortation, that coercion was never required too.
So it's a non-starter, pure and simple, however attractive in theory.
Update - examples of historical track record (as requested in comments)
One of the comments asks for more examples of misuse of vaccines, and the resulting long term historical distrust of modern public medicine, related to vaccines and more broadly, modern health medicine campaigns.
I think Lowes & Montero “The Legacy of Colonial Medicine in Central Africa” (2018) PDF direct link is a good starting paper, so I'll quote from its summary:
Over the course of several decades, millions of individuals were subjected to medical examinations and forced to receive injections of medications with dubious efficacy and with serious side effects, including blindness, gangrene, and death. The sleeping sickness campaigns constituted some of the largest colonial health investments, and for many, these campaigns were their first exposure to modern medicine (Headrick, 1994; Lachenal, 2014).
There is a large body of anecdotal evidence from Africa of mistrust in medicine leading to under-utilization of health care [note 2]. Relatedly, research in developing countries has highlighted that even when there is access to high-quality preventative and therapeutic tools, demand remains puzzling low (Dupas, 2011; Dupas and Miguel, 2017; Banerjee et al., 2010). Motivated by work from anthropology and history which links colonial medical campaigns against sleeping sickness and mistrust in medicine (Feldman-Savelsberg et al., 2000; Lachenal, 2014), we hypothesize that the colonial medical campaigns may have had a series of unintended effects on both beliefs about modern medicine and the success of modern health interventions. The campaigns may have affected use of medicine because: villagers were forced to receive injections, many of the medications had serious negative side effects, and the medications were ineffective. Additionally, the campaigns may have also caused the spread of contagious diseases because of the re-use of unsanitary needles during the campaigns (Pépin, 2011; Lachenal, 2014).
Note 2: For example, during the 2014 Ebola outbreak in West Africa, some communities rejected health workers and did not follow recommended practices to avoid transmission of the virus (Blair et al., forthcoming). In northern Nigeria,
communities boycotted the polio vaccination leading to a large outbreak of a nearly eradicated disease (Jegede, 2007).
Also with useful references, "Determinants of trust in the ﬂu vaccine for African Americans and Whites", by Freimuth et al (2017), which states in its summary that:
...the American Academy of Arts and Science (AAAS), calls for research on the role of trust in vaccine decisions, particularly within “at-risk communities”where social norms may contribute to lower vaccine trust and greater vaccine hesitancy (AAAS, 2014). Reﬂecting upon both calls, we recognized the need for research on trust as it relates to vaccine disparities, as growing evidence indicates African Americans experience greater distrust and vaccine hesitancy when compared to their White peers (Quinn et al., 2017) .... Major theoretical work surrounding vaccine trust comes from the World Health Organization's (WHO) Strategic Group of Experts on Vaccination (SAGE). SAGE hypothesizes that trust is a major factor in vaccine hesitancy, contributing to vaccine delay and refusal (MacDonald, 2015). Trust inﬂuences vaccine hesitancy at many levels, including “trust in the effectiveness and safety of vaccines, the system that delivers them, including the reliability and competence of the health services and health professionals and the motivations of policy-makers who decide on the needed vaccines” (MacDonald, 2015, 4162) ...[polling data shows that] trust in pharmaceutical companies is at an all-time low (Harris Poll, 2015; Gallup Poll, 2016). A recent study conﬁrmed 65% of American adults trust the CDC and 63% trust the FDA (Kowitt et al., 2017). Trust in the role these institutions play in the vaccine process is less studied. Qualitative investigation revealed widespread mistrust in the motives that drive pharmaceutical companies, as well as some skepticism regarding the competence of government agencies in developing appropriate inﬂuenza vaccines (Quinn et al., 2016).
Sociological evidence demonstrates that in general, African Americans are significantly less trusting than Whites, likely due to historical and contemporary experiences of discrimination and racialized social norms (Smith, 2010). Medical distrust is also widespread in the Black community, stemming from a long history of medical racism and abuses and reinforced through ongoing experiences of discrimination in health care (Freimuth et al., 2001;
Gamble, 1997). Numerous studies have conﬁrmed the impact medical racism and events like the Tuskegee Syphilis Study have had on trust in medical research (McCallum et al., 2006), on trust in physicians (Benkert et al., 2006), and on trust in the healthcare system more broadly (Boulware et al., 2003) ...
Sadly, much of the distrust is self-created - by unethical behaviour within highly developed countries, towards countries in developing regions and at tomes towards minorities and the less privileged. Therefore much of the history in this area, is racially and ethnically slanted, as the above studies demonstrate.