COVID-19, HPV, smallpox and polio: four vaccine successes

Vaccines changed the pandemic’s course. So why are people still vaccine-hesitant?

An illustration of a sea of large bottles with a label that says "vaccine" on them and a person standing on one of the lids with a board in front of them that they're pointing to with an illustration of various viruses and DNA on the board.
[Muaz Osman/Al Jazeera]

Most people will agree the key to easing COVID-19 restrictions has been the use of vaccinations. Although they are imperfect in that they do not prevent a person from getting COVID-19 itself, they do offer a good level of protection against serious illness.

Some argue their protection wanes over time. This is true, which is why it is recommended that we get booster shots, much like with the flu vaccine or many childhood immunisations that are given over years to ensure long-lasting protection.

To those who say natural immunity as a result of getting the virus is superior to the protection offered by vaccines, I would respond that the risks of adverse effects associated with the vaccines are far less than the very real risks associated with contracting a new virus that is known to cause widespread and even long-term damage to the human body.

Although work is being done to develop second-generation COVID-19 vaccines that will offer better and longer-lasting immunity, and more needs to be done to get the current vaccines to developing nations, it is fair to say these current vaccines have changed the course of the pandemic.

According to recent statistics, 66.3 percent of the global population has received at least one dose of a COVID-19 vaccine with countries like the United Arab Emirates, Chile and Singapore leading the way with more than 90 percent of their populations having had at least two doses.

The emergence of variants such as the now-dominant Omicron caused some concern about the effectiveness of vaccines given the virus’ mutations, but evidence shows booster doses offer protection against variants. Despite this, boosters are not being taken up in the same way the initial doses were. Singapore is a world leader, having offered everyone over 12 years of age a booster five months after their initial two doses and has an uptake of about 77 percent, significantly lower than its uptake for the first two doses. By comparison, the United States fares worse. It has vaccinated 66.8 percent of its total population with two doses, but only 36.1 percent of its population has had the booster.

Vaccine uptake

Vaccine uptake is vital if we are to defeat COVID-19. As with any vaccine programme, eradication or protection from the disease relies on enough people having the vaccine(s) so the pathogen that causes the illness can no longer find a host to infect and multiply in. Enough people within a population need to have the vaccine so those who are unable to do so – such as those who are too young or have medical issues where the vaccine either would not work or cause more harm than good – can also be protected through the lower prevalence of disease within their communities. Without high uptake, our lives, and those of our loved ones, will remain at high risk from this devastating virus.

So why are people, more than a year after COVID-19 vaccines became available, still hesitant to get their shots? Vaccine hesitancy, in fact, is thought to have become worse since the pandemic.

The reasons behind hesitancy are multifactorial and relate to several context-specific factors as well as being influenced by socioeconomic reasons, many of which change depending on global location. COVID-19 vaccine hesitancy has been linked to:

  1. Lack of effective public health messaging,
  2. The spread of misinformation, disinformation, conspiracy theories, and rumours online,
  3. Historical unethical research involving ethnic minority groups as well as structural racism,
  4. People from lower socioeconomic backgrounds and lower literacy levels not having access to accurate and appropriate information,
  5. Barriers to access, including vaccine delivery time, location, and cost related to socioeconomic inequalities and marginalisation

Vaccine hesitancy – undoing progress

In 2019, the World Health Organization (WHO) declared vaccine hesitancy one of the top 10 threats to global health. They said vaccination is one of the most cost-effective ways of avoiding disease by preventing 2 to 3 million deaths a year.

“Vaccine hesitancy – the reluctance or refusal to vaccinate despite the availability of vaccines – threatens to reverse progress made in tackling vaccine-preventable diseases,” according to the WHO.

When we are born, we are exposed constantly to different, mostly harmless – and beneficial – viruses, bacteria and other microbes. However, some of these cause disease which often confers lifelong immunity, but can also kill us or lead to complications. Vaccines are designed to offer protection without these risks.

It is easy for people alive today, particularly younger generations, to forget how essential vaccines have been in the eradication of many deadly infectious diseases. Along with clean water, immunisations have done more to prevent child deaths than any public health advance ever. Apart from the COVID-19 pandemic, here are some of the other times that vaccines have changed our lives:

Smallpox and monkeypox

The emergence of monkeypox in countries where the disease has not been previously found has brought the smallpox vaccine back into the public eye. There is no specific vaccine for the monkeypox virus, which comes from the same orthopox family of viruses as smallpox.

Smallpox, a deadly disease that killed a third of those infected, was declared eradicated by the WHO in 1980 thanks to a global vaccination and surveillance programme launched in 1967. Routine vaccination of the American public against smallpox stopped in 1972, while in the UK, it stopped in 1971. The last known natural case of smallpox was in 1977 in Somalia. The eradication of smallpox is one of the biggest public health successes in history.

Eradication means people no longer needed to be immunised for smallpox as the disease no longer exists in the natural world, but this may also be contributing to why we are seeing a rise in monkeypox cases. The vaccine used to immunise against smallpox offers 85 percent protection against the monkeypox virus, so one theory is people who did not need the smallpox vaccine do not have any antibodies against viruses from the same family so are at a higher risk of contracting monkeypox should they come into close contact with someone who is infected. The smallpox vaccine is now being used by many countries to vaccinate those who have had close contact with monkeypox cases.

HPV vaccine

Another vaccine that is proving highly successful in preventing disease and death is the human papillomavirus (HPV) vaccine. This is a two or three-dose vaccine given to teenage girls (and boys in some countries) and the regime will vary slightly depending on location and age.

HPV is mainly transmitted through sexual contact and most people are infected with HPV shortly after the onset of sexual activity. The human papillomavirus is responsible for almost all cervical cancer cases worldwide but has also been associated with mouth, throat, anal and genital cancers. Among women globally, cervical cancer is the fourth most common cancer.

In 2020, there were an estimated 604,000 new cases and 342,000 deaths. A recent study showed the HPV vaccine dramatically reduced cervical cancer rates by up to 97 percent in women in their 20s who were offered it at age 12 to 13.

This is an incredible feat of modern medicine, so much so that the World Health Assembly, the WHO’s decision-making body, adopted a global strategy to eliminate cervical cancer in 2020. To achieve this, countries must reduce cases to four per 100,000 women a year by achieving the following targets:

  1. 90 percent of girls fully vaccinated with the HPV vaccine by age 15,
  2. 70 percent of women screened by age 35 with a high-performance test, and again by age 45.
  3. 90 percent of women identified with cervical disease having received treatment (90 percent of women with pre-cancer treated; 90 percent of women with cancer managed).

As a doctor, it is incredible to think that in the not-too-distant future my colleagues will not have to have the same difficult conversations that I have had with some of my patients about their diagnosis of cervical cancer. All of this comes down to the vaccine.

Polio vaccine

Another major vaccine success story worth reminding ourselves of is the polio vaccine. Polio is a contagious viral illness, spread by coughing and sneezing. A severe case of polio involves nerve injury that can lead to paralysis, breathing difficulties and even death.

It was once a disease feared worldwide, striking suddenly and paralysing – mainly children – for life. Vaccination means polio is now very rare in most parts of the world. For most of us, the polio vaccination programme has meant that we have not had to live with the horror and heartbreak of seeing loved ones suffer from this debilitating and deadly disease.

It is now mainly found in two countries: Afghanistan and Pakistan. The WHO and the Global Polio Eradication Initiative are working to eradicate polio from its last strongholds with new vaccines and accelerated vaccination programmes.

Building trust

Vaccines have proven time and time again they are safe and effective ways of protecting us against previously deadly diseases. Global vaccination programmes have dramatically decreased the number of cases of diseases such as rubella, mumps, whooping cough, tuberculosis, tetanus and haemophilus influenzae type B to name but a few.

But vaccine hesitancy still looms large and poses a danger to public health as a whole. It is one of the factors thought to be contributing to a decrease in the uptake of the measles, mumps and rubella (MMR) vaccine in some countries.

The UK Health Security Agency and NHS have recently launched a campaign to increase the uptake of the MMR vaccine in England. Two doses are necessary for optimum protection and, due to the highly infectious nature of measles, a sustained 95 percent vaccine coverage is required to prevent outbreaks. Between July and September last year, the most recent figures available, just 88.6 percent of children had had their first MMR dose by the age of two while only 85.5 percent had had both doses at the age of five.

This means that more than one in 10 children aged five in England are not up to date with their two doses of the MMR vaccine. Measles is a highly contagious disease that can spread quickly when population immunity levels drop and can lead to complications such as pneumonia and brain inflammation.

Healthcare professionals play an important role, as trusted members of the community, in ensuring the correct information about vaccines gets to their patients – but they cannot be relied on alone. Governments and health policymakers also play an essential role in promoting vaccination, educating the general public, and implementing policies that reduce public concerns about health risks associated with vaccines.

Different countries, populations and religious groups will have distinct reasons for being hesitant to take up certain vaccines and messaging needs to be adjusted to be appropriate and specific to them.

Some countries have implemented sanctions to tackle hesitancy. Germany, for example, implemented fines for parents who did not vaccinate their children against measles. Meanwhile, school entry requirements that include specific vaccinations have been a routine public health practice in some countries for many years. France has made 11 routine childhood vaccinations mandatory; unvaccinated children cannot be enrolled at nurseries or schools. In Australia, parents of children who are not vaccinated are denied welfare payments.

But it is not just about getting the right messaging out. Misinformation also needs to be curbed and social media platforms need to take responsibility for this and partner up with official healthcare bodies to ensure there is widespread promotion of evidence-based information explaining the benefits of vaccination.

Vaccine hesitancy is threatening to undo the historical achievements made in reducing the burden of infectious diseases, which have plagued humanity for centuries. If we don’t tackle this issue head-on, we risk the future health of not only unvaccinated children but that of the wider community as well.

Source: Al Jazeera