Variations in COVID-19 vaccination uptake among people living with mental health conditions in Northern Ireland

Plain English Summary

Globally, there are mixed reports on how many people with mental health conditions are vaccinated.

In late 2021, the UK's Joint Committee on Vaccinations and Immunisation identified people living with mental health conditions (such as schizophrenia, bipolar disorder and major depressive disorder) as a priority group for COVID-19 vaccinations.

This is because, compared to the wider UK population, people with mental health conditions are thought to be more at risk of SARS-CoV-2 infection. They are also known to have higher rates of COVID-19 related hospital admissions and death.

Why did we carry out this work?

It is important to understand what factors could make a person more or less likely to receive their COVID-19 vaccines. This helps us to understand how fair and effective the vaccination programme is.

As of Ocobter 2021, Northern Ireland (NI) has the lowest uptake of COVID-19 vaccinations of all UK nations. It is also known to have higher rates of mental health conditions.

We wanted to see if there is a link between a person having a mental health condition, and their likelihood of being vaccinated. Here, we looked at:

• How many people in NI have been vaccinated (uptake)?
• How many people are prescribed psychotropic medications?
• What medications are being prescribed?
• Does their prescription indicate whether a person is more or less likely to be vaccinated against COVID-19?

It is also known that vaccination rates vary depending on whether an area is more or less deprived. People in less deprived areas are more likely to get vaccinated, but the reason why is not entirely clear. We, therefore, also investigated if variations in mental health could explain this pattern.

What are psychotropic drugs? Why did we use them as a measure of mental health?

Psychotropic drugs are any medication used to treat mental health conditions.

We could not directly 'count' how many people had a mental health condition. This is because we did not have access to the relevant patient healthcare data, such as GP diagnoses.

Therefore, we used the prescription of these medications as the measure for someone having a mental health condition.

Despite its limitations, we found this to be a reliable method of examining mental health treatment across NI.

What did we do?

Our data sources

Our researchers created a national cohort using a unique dataset made up of information on:

• Medication dispensed by community pharmacists

• Population data (such as age and sex)

• Vaccination status

We used also used additional data sources to help us identify who was and was not a resident of NI. This included emergency department attendance, and secondary care Patient Administration System, data. These data sources were linked together using the unique qualifier.

Find out more about: Unique identifiers

The resulting dataset was then anonymised, and made available to us, through the Business Services Organisation's online Secure Research Platform.

Data limitations

We did not have access to several strands of data and could not included them in our analyses. This includes data related to a person's primary care, diagnostics or ethnicity.

Furthermore, the Patient Administration System data included all NI hospital sites, but not all mental health or learning disability settings.

Our study population

In total, we looked at the data of 1,433,814 NI residents. These people were all aged 18 and over by 1 December 2020, and still alive on 9 September 2021.

We did not include people living in institutional housing, such as care homes. This is because they had their own specific interventions, and their vaccination uptake is known to be very high. Meaning their inclusion would have skewed our results.

Health status

We also accounted for a person's physical health.

To do this we adapted a research method that has been validated by several earlier studies. Here, we recorded the number of non-psychotropic prescriptions a person had. However, these medications were only counted if they were prescribed at least twice in the 6-month period before the vaccination programme began.

Psychotropic medications

We used prescription data to look at four different groups of psychotropic medications:

Psychotropic Medication	Description
Antidepressants	A group of medications mainly used to treat major depressive disorder.
Antipsychotics	This group of medications is mainly used to treat psychosis associated with Schizophrenia and other psychotic disorders.
Anxiolytics	A group of medications used to treat anxiety.
Hypnotics	Commonly known as sleeping pills, this group of drugs is used to induce sleep and to treat insomnia.

Again, for these medications to be included in our analyses, they had to be prescribed twice within the six-months before the vaccination programme.

What did we find?

How many people were vaccinated?

We found that 81% of the NI residents we studied received at least one dose of a COVID-19 vaccine.

How many people were given psychotropic medications?

Nearly one-in-five people (or 19%) of our study population were prescribed at least one type of psychotropic medication:

• Antidepressants were the most prescribed medication, being used by 21% of women and 12% of men.
• Antipsychotics were the least common drug, being only prescribed to 2% of people.
• Anxiolytic and hypnotic medications were both prescribed to around 3% of the population.

Were physical and mental health linked?

Yes. Our results showed that being physically ill was strongly associated with the use of psychotropic medications, especailly antidepressants. This supports the findings of many previous studies.

Were people prescribed with psychotropic medications less likely to be vaccinated?

Yes.

At first, our model suggested that people on any psychotropic medication were more likely to be vaccinated than those who were not.

However, we then accounted for socio-demographic and health characteristics in our analyses. Afterwards, the model found psychotropic medications to be a significant risk for lower vaccine uptake. This means that people using these medications had a higher risk of not being vaccinated.

Did our results vary depending on the type of medication?

Yes, there was some variation depending on the type of medication prescribed.

We found that antidepressants did not affect a person's likelihood to get vaccinated.

In contrast, treatment with anxiolytics, anti-psychotics and hypnotics all indicated lower odds of vaccination. On their own, anxiolytics and anti-psychotics had the greatest lowering affects.

The lowest odds for vaccination were found in people under the age of 40, prescribed both anxiolytics and hypnotics.

Did mental health explain location differences in vaccine uptake?

No. The prescription of psychotropic drugs did not explain why people living in less deprived areas had higher vaccine uptake, than those in more deprived areas.

Why is this important?

This may be the first nationwide study to look at COVID-19 vaccination uptake among people with common and severe mental health conditions.

Our results show that people being treated with anxiolytic and anti-psychotic medications, are much less likely to be vaccinated. This highlights an urgent need for new and innovative methods to encourage people with mental health conditions to be vaccinated.

Note

This plain English summary was reviewed with the support and feedback of the DaC-VaP Patient and Public Involvement Leads.

Find out more on: Meet our team

Acknowledgement

The study authors would like to acknowledge the help provided by the staff of the Honest Broker Service (HBS) within the Business Services Organisation Northern Ireland (BSO).  The HBS is funded by the BSO and the Department of Health (DoH).  The authors alone are responsible for the interpretation of the data and any views or opinions presented are solely those of the author and do not necessarily represent those of the BSO.