How Chronic Substance Use And Addiction Increases Your Risks Of Infectious Diseases, Including The Coronavirus

The chronic use of alcohol and nearly every type of drug that people misuse or become dependent upon, taxes the body, and more specifically, the immune system of an individual. This potentially results in compromised immune system functioning.

The use of most drugs that many people use recreationally and become dependent upon, including alcohol, leads to the suppression of the ability of the immune system to fight off infections, viruses, illnesses, impact the recovery from injuries and increase your risk of cancer development. In general, severe chronic alcoholics and drug addicts are considered immunocompromised hosts.

Individuals who binge or use extremely high amounts of drugs and alcohol also weaken the immune system by exhausting themselves. The major drugs that affect the immune system are discussed below.

What Is The Immune System?

The immune system is comprised of a number of tissues in the body that fight infection. Conditions that compromise the immune system can result in an individual being more susceptible to contracting an infectious disease, becoming injured because their body isn’t functioning normally or struggle to recover from illnesses that the individual may have already.

Different Types Of White Blood Cell Have Different Functions.

Leukocytes, or white blood cells, are important cells of the immune system that are produced and stored in many areas, including the spleen, lymphatic tissues and bone marrow. They help to protect the body against foreign substances, microbes and infectious diseases.

Leukocytes circulate throughout the body and monitor for substances that need to be eliminated from the body. There are two basic types of leukocytes:

  • Phagocytes attack and grind up invaders.
  • Lymphocytes allow the system to recognise previous invaders and then help destroy them. There are two types of lymphocytes: B lymphocytes and T lymphocytes.

Alcohol & The Immune System

Those who consume alcohol at higher-than-moderate levels experience double the rate of pneumonia and increased rate of tuberculosis, hepatitis C and cancer, as well as greater exposure to hepatitis B, HIV and other infections.

Acute Alcohol Consumption & Adverse Immune System Response

Most of the discussion on the topic of immunodeficiency and alcohol centers around long-term, chronic alcohol consumption. And yet, someone who participates in binge drinking, even once per month or moderate consumption, may be susceptible to the ill-effects of alcohol on immune system health.


Alcohol interferes with the chemical signals from white blood cells called cytokines, which can cause an autoimmune response if produced in larger than normal quantities, or an immune system deficiency in cases when these levels are decreased.

T-Cell Functioning Normally

Alcohol consumption also disrupts normal T-cell function, leaving someone at greater risk of bacterial and viral infection.

Did You Know:

A single episode of binge drinking can result in an immune system failure against exposure to illness within the first 24-hours of initial consumption.

Chronic Drinking & Immunodeficiency

Chronic consumption of alcohol impairs the vital immune system to a great degree. Individuals who consume alcohol regularly and at higher levels than the liver can process it shows increased levels of immunoglobulins within their bloodstream, indicating an autoimmune response.

Immunoglobulins, or antibodies, are proteins that seek to identify or “mark” bacteria and viruses for white B-cells and T-cells to target. In the case of chronic alcoholism, these cells may begin to mark healthy cells in the body, throwing this intricate and vital system into an autoimmune response, or self-destructive mode.

Another effect of long-term alcohol exposure is a deficient immune response, due to the interruption of normal immune system function. In these cases, a person may suffer reduced levels of white cells, leaving them far more susceptible to illness and disease. Alcohol and immunodeficiency have long been correlated, though the mechanism for this process is still being studied.

Alcohol Consumption & Disease

Chronic alcohol consumption is associated with many dangerous diseases, including pneumonia, tuberculosis, human immunodeficiency virus (HIV), hepatitis B and C, septicemia and other infections, autoimmune diseases, COVID-19 and cancer.

Not only does alcohol impair the immune system, but it could also lead to other conditions, like leaky gut syndrome, in which bacteria from the bowel seep or “leak” through the walls of the intestines. These bacteria can lead to infection. However this is still being investigated by researchers.

Alcohol, Acetaldehyde & Cancer

For decades, researchers have known of the correlation between increased rates of certain cancers and problem drinking, but the mechanism by which alcohol causes cancer was not known.

Alcohol is not carcinogenic, but once alcohol is metabolised in the bowel and liver, very toxic acetaldehyde is released. Acetaldehyde, also found in tobacco smoke, is a toxic human carcinogen.

Within the intricate immune system are a specialised white cell called natural killer cells (NK). One of the specialised functions of NK cells is there ability to detect and rid the body of cancer. Alcohol is believed to impair NK cell function, leaving the body more vulnerable to malignancies.

Alcohol & Immune System Health

Damage to the immune system from binge drinking or chronic alcohol consumption, in many cases, is reversible. Reducing or stopping consumption of alcohol is a key component, along with a balanced diet.

To keep health risks from alcohol to a low level, the UK Chief Medical Officers (CMOs) advise it is safest not to drink more than 14 units a week on a regular basis. Though many craft beers may contain higher levels of alcohol on par with wine. Drinking slowly can also provide the liver time to process the alcohol.

Tobacco & The Immune System


Research indicates a clear relationship between chronic use of tobacco products and decreased immune system functioning.

Chronic tobacco use is associated with:

  • Decreased antibody formation in both animals and humans
  • Decreased lymphocyte proliferation in both animals and humans
  • Decreased availability of antioxidants in heavy smokers
  • Increased infection susceptibility to nearly every bacterial and viral infection tested
  • Extreme susceptibility to respiratory infections as would be expected

A small study reports that, aside from lung cancer, emphysema and heart disease, cigarette smokers also have weakened immune systems affecting their dental health Amon other things.

Scientists from Case Western Reserve University School of Dental Medicine found that smoking reduces the ability of pulp inside teeth to fight illness and disease. This could also explain why so much damage can be done to your teeth when smoking chronically as your immune system is further weakened. This is especially true when smoking is also done in combination with alcohol or other prescribed or illicit drugs.

Opioids & The Immune System

Opioid drugs all originate from substances derived from the opium poppy plant. Their primary medicinal use is to control severe pain. As a side effect, many of these drugs produce significant feelings of euphoria and are high potential candidates for misuse and the development of physical dependence.

It has long been established that chronic use of opioid drugs, such as morphine, heroin, codeine, Vicodin, OxyContin, tramadol, etc., results in hindering the immune system’s ability to fight off both viruses and bacterial invaders. Research suggests that morphine, the prototypical opioid drug, suppresses the activity of the different types of white blood cells that are important in fighting off infections. This suggests that individuals who chronically misuse opioid-based drugs are susceptible to any number of infectious diseases and are more likely to experience respiratory infections like colds and influenza (due to a combination of the drugs inhibiting respiration and suppressing the immune system), cardiovascular infections, and issues with the liver and kidneys.

Example Of Effects To Immune System When Morphine Use Is Also Present. This Is The Same Response With Any Other Forms Of Opioids/Opiates

It is also probably safe to assume that not all opioid drugs have similar effects on the immune system; however, the specific effects on immune system functioning of each opioid drug alone are not well known.

Currently, it is probably safest to assume that opioid drugs in general suppress immune system functioning. When taken in larger doses over lengthy periods of time, drugs that combine opioids with medications like paracetamol, such as Solpadeine Max, can suppress the immune system and result in liver toxicity, which further suppresses the ability to fight infection.

Marijuana & The Immune System

There are a number of animal models that suggest that chronic use of cannabis products may be associated with decreased immune system functioning.

However, these findings are less clear in adult humans. However, it is safe to conclude that children and adolescents who use cannabis products regularly most likely do experience suppressed immune system functioning. Research in this area is still underway, however results so far do show that cannabis products do suppress the individuals immune System.

Cocaine & The Immune System

As with other drugs, chronic use of cocaine affects the immune system and leads to an increased susceptibility to develop infections. One interesting aspect of cocaine misuse is its suppression of the thymus gland that produces T lymphocytes, which attack foreign cells. Chronic cocaine misuse appears to hinder the ability of certain groups of the cells to develop and also increases the rate of the number of the cells that undergo programmed cell death prematurely (apoptosis). The more cocaine an individual uses, the more cells that die off as a result.

Some of the immune system-related issues in cocaine users appear to come from secondary environmental factors; however, some of these issues stem directly from changes in normal immune function. In a study published in May 2014 in the journal Addiction Biology, researchers from Spain and the U.S. looked at the types of immune system disruptions that can appear in people addicted to cocaine. They also looked at the impact of immune system dysfunction on the severity of cocaine addiction.

Cocaine & Immune Function

Cocaine users can place an undue burden on their immune systems by doing such things as sharing needles and displaying impaired judgment that leads to participation in unsafe sexual practices or certain other high-risk behaviours.

However, the stimulant drug also has a harmful effect on organ systems throughout the body, including the respiratory system, the cardiovascular (heart and blood vessel) system and the central nervous system (brain and spinal cord).

In addition, the drug has the ability to alter the health of several key components of the immune system. For example, in a study published in 2013 in the Journal of Leukocyte Biology, a team of U.S. researchers linked the use of cocaine to damaging changes in some of the key cells that act as a frontline defense against the human immunodeficiency virus (HIV) and other highly serious forms of infection.

In the study published in Addiction Biology, researchers from The Scripps Research Institute and 10 Spanish institutions used an examination of 82 people recovering from cocaine addiction to explore the immune system changes triggered by chronic exposure to the drug.

They also examined the impact that increasing immune system dysfunction has on the severity of cocaine addiction, as well as on the odds that an addicted person will develop a mental illness such as an anxiety disorder, schizophrenia or some other psychosis-related condition, a mood disorder (depression or bipolar disorder) or a personality disorder.

For the sake of comparison, a group of 65 people unaffected by cocaine addiction also took part in the study. The researchers concluded that a cocaine addict can experience as many as 11 damaging changes in key protein cells that help provide normal immune function. Some affected individuals only develop one or two of these changes, while others develop as many as nine or more.

After comparing the number of immune system alterations present in an individual to the intensity of his or her cocaine addiction, the researchers also concluded that people heavily impacted by immune cell dysfunction (at least nine specific alterations) tend to have more severe addiction symptoms.

In addition, they concluded that those cocaine-addicted individuals with highly compromised immune systems have clearly elevated risks for a co-occurring case of a personality disorder, anxiety disorder, schizophrenia/psychotic disorder or a mood disorder. The particular level of risk elevation varies with the type of mental illness under consideration. In addition to their work with humans, the study’s authors conducted experiments on mice that further confirmed the link between chronic cocaine use and certain critical changes in immune system function.

They believe that their findings can potentially help doctors make more accurate assessments of people seeking treatment for cocaine-related problems, as well as making it easier to identify effective treatments.

Issues With Injecting Drugs & Other Risky Behaviours


While the majority of research indicates that chronic misuse of any class of drugs result in decreased immune system functioning and an increased susceptibility to develop a number of different issues, there are various other methods by which individuals with substance use disorders and alcohol use disorders increase their susceptibility to the risk of contracting infections.

Did You Know:

People who inject drugs are 22 times more at risk of contracting HIV compared with the general population.

Drugs that are commonly injected include morphine, heroin, methamphetamine and cocaine. Injection of these drugs and sharing needles accounts for a significant proportion of cases of HIV per year and is also a major factor in the spread of hepatitis C, which is a serious and potentially fatal disease of the liver. Obviously, needle sharing as a result of drug misuse is a major factor in the spread of these serious infectious diseases. This is why adopting and religiously sticking to harm reduction strategies are so important.

In addition, the use of many of these drugs increases the likelihood that individuals will engage in other risky behaviours, such as unprotected sex and other dangerous activities. This can result in an increased number of sexually transmitted diseases, the spread of HIV and the spread of diseases like hepatitis B and C. This also then has a knock-on effect for other people within the individuals community who may also be put at greater risk because of their behaviour.

Chronic drug misusers engage in a number of other behaviours that open them up to the risk of developing infections. Oftentimes, these individuals neglect aspects of their personal hygiene and nutrition. They often engage in bingeing behaviours that result in a number of different stresses on bodily systems and also lead to increased susceptibility to infections and diseases. Individuals who misuse multiple drugs multiply their risk factors significantly.

For example, those who inject heroin are more likely:

  • To have ulcers at injection sites where infections begin and they are neglected, causing bigger issues and opening themselves up to greater health risks.
  • Neglect eating a balanced diet, meaning that their body may lack the essential nutrients it needs to repair itself.
  • Don’t wash regularly, meaning new infections are more likely to set in and any pre-existing ones become worse.

Individuals with chronic substance use disorders very often have comorbidity (co-occurring) issues such as psychological or psychiatric disorders, such as depression, anxiety disorders and personality disorders, along with multiple physical health conditions.

People with these mental health issues are also known to be particularly susceptible to infections and diseases of all types. Thus, individuals with substance use disorders typically have increased chances of catching an infectious disease through a number of different pathways.

Mental Health & The Immune System

An imbalanced immune system has long been known to influence a variety of mood conditions including anxiety, obsessive-compulsive disorders and depression. Indeed, patients treated with drugs that suppress the immune system or suffering from deficiency in the immune response are more likely to show changes in mood and behaviour. Although several clinical studies support these findings, the exact mechanism by which the immune system influences mood and emotional state is still not clear. Our recent studies have shown T-lymphocytes, one type of immune cells present in our blood, play a significant role in regulating the emotional response in experimental animals. We have also identified a particular subtype of T lymphocytes that could directly modify the way the brain works.

Things like constant stress and other hormones which are released during our various moods can also affect our immune responses to viruses, bacteria and conditions such as Covid-19. Other changes can also be seen in the image above.

Substance Use & COVID-19

Monitoring substance use and SUD during the pandemic is essential, as people who engage in substance use or present with SUD are at greater risk for COVID-19, and the economic and social changes resulting from the pandemic may aggravate SUD. There have been several reviews focused on COVID-19 in relation to substance use (including alcohol addiction) which show that due to the individual having misused substances chronically, they become at a greater risk of developing COVID-19.

The way your body fights COVID-19 can also create antibodies within your immune system.

Using opioids during the COVID-19 pandemic could also increase your risks of developing COVID-19 as well. However research is still ongoing.

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Published by Drink ’n’ Drugs

Providing useful, relevant, up to date information and support for those suffering from active addiction or those who are in recovery.

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