Vaccine

A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future. Vaccines can be prophylactic (example: to prevent or ameliorate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (e.g., vaccines against cancer are being investigated).

Risk in developing ME/CFS
According to the 2018 version of The Clinician’s Vaccine Safety Resource Guide Vaccines: "Vaccines currently routinely recommended to the general population in the U.S. have not been shown to cause fibromyalgia or chronic fatigue syndrome (CFS)."

A 2015 complete population study of data from 2009 to 2012 in Norway, following the country's mass vaccination during the 2009 influenza A (H1N1) pandemic, found that vaccination produced no increased risk of ME/CFS. By contrast, infection with flu more than doubled the risk of developing CME/CFS.

Some have reported developing ME/CFS after receiving vaccinations for foreign travel but a causal relationship has not been shown.

In one case of a 43-year-old man who developed CFS after having five vaccinations, with no previous ill health, Dr. Chris Exley and team at the Birchall Centre at Keele University in Staffordshire, UK, in 2008 "proposed that the cause of the CFS in this individual was a heightened immune response, initially to the aluminium in each of the adjuvants and thereafter spreading to other significant body stores of aluminium." However, under this hypothesis, Dr. Exley anticipated that the mass human papillomavirus (HPV) vaccination program then recently begun in the UK would carry related risks, as that vaccine also uses aluminium-based adjuvant. That was not borne out: a 2013 study concluded there is no evidence the HPV vaccine leads to developing chronic fatigue syndrome.

Risk in developing Gulf War Illness
Vaccinations have been proposed as an etiological factor in Gulf War Illness, especially the mass vaccinations given prior to military deployment.

Vaccination in the presence of elevated cortisol levels can drive cytokine expression toward Th2 dominance.

Vaccines in ME/CFS and Fibromyalgia patients
Risk of contracting an infectious disease such as COVID-19, flu or other viruses and bacterial diseases depends on exposure to the infection and the strength of the person's immune system. People with a weakened immune system are known as immunocompromised or immunosuppressed, for example people with AIDS, diabetes or malnutrition, or people taking immunosuppressant medications.

ME/CFS includes immune symptoms including a sore throat, swollen lymph nodes, and flu-like symptoms, but patients are generally not considered to be severely immunocompromised, and immunosuppressant medications are unlikely to be used by most ME/CFS patients, this means that ME/CFS patients are not significantly more likely to experience life-threatening complications from COVID-19, viral or other infections―however some patients are already very severely ill due to very severe ME.  This means most ME/CFS patients would not be considered to be at very high risk of serious COVID-19 complications unless they had other known risk factors such as obesity, older age or other illnesses.

Viruses generally are known to increase the severity of ME/CFS in a proportion of patients, either temporarily or permanently; there is a known risk of deterioration after a virus although it is unclear exactly how many ME/CFS patients experience this.

Vaccine effectiveness in ME/CFS patients
A study in 2012 assessed immune system responses to the flu vaccine in people with ME/CFS, and took biological samples that showed the immune systems of ME/CFS patients responded similarly to those of healthy people. The study indicated a similar antibody response in ME/CFS patients after the vaccine, and it was likely to be as effective in protecting ME/CFS patients against flu. The study did not include a long-term follow-up to assess duration of vaccine effectiveness or overall effect on ME/CFS symptoms.

Immunocompromised people and vaccines
People who are severely immunocompromised either by a particular disease or treatment are advised to get additional vaccines due to their suppressed immune system being unlikely to fight off infections. Immunocompromised people who choose to have a vaccine may be given a specific type of vaccine more suited to their needs, for example a flu vaccine injection instead of the flu nasal spray vaccine (because the flu nasal spray is a live vaccine).

The first COVID-19 vaccines to be approved in the United States, UK and European Union are the Pfizer-BioNTech and Moderna messenger RNA (mRNA) COVID-19 vaccines, mRNA vaccines do not contain live or weakened COVID-19, so these vaccines are suitable for severely immunocompromised people as well as people in the general population and cannot cause COVID-19.

Autoimmunity and ME/CFS
The unproven autoimmune hypothesis states that a subtype of ME involves autoimmunity, which is an overactive immune system rather than a weakened immune response. Evidence for this theory is limited.

Live vaccines
Live vaccines contain either weakened or killed pathogens which cannot cause disease. Different types include: Live vaccines may not be suitable for some people, for example those who have received an organ transparent, or those with a weakened immune system, or people with long-term conditions.
 * Whole-pathogen vaccines, for example the Harvix Hepatitis A vaccine, these provide very good immunity for either a lifetime. or a very long period of time
 * Subunit vaccines that just contain the antigens needed.

Inactivated vaccines
These may contain all the pathogen, which has been killed or inactivated in a lab, for example by heat or another method, or just the antigens needed, for example the newer whooping cough (pertussis) which has a lower risk of fever or swelling at the injection site. Protection is not as strong as with live vaccines, so several booster shots are usually needed.

Toxoid vaccines
These contain chemically inactivated toxins, for example the diphtheria and tetanus vaccines that protect against those bacteria.

Subunit, recombinant, polysaccharide and conjugate vaccines
These vaccines do not contain the whole virus or pathogen, they may contain just particular pieces, e.g. a protein, sugar or part of the shell of the pathogen. This creates a very strong targetted immune response. Recombinant vaccines have been around since the 1970s and use DNA technology to combine two or more sources, e.g., antigen in the hepatitis B vaccine is a hepatitis B virus protein produced by yeast cells into which the genetic code for the viral protein has been inserted into. These may use virus-like particles (VLP) from the shell of a virus to cause immunity without the risk of infection.

Subunit, recombinant, polysaccharide and conjugate viruses are suitable for people with weakened immune systems, chronic illness or other long-term health conditions as well as the general population. Examples include the current Hib (haemophilus influenzae type b) vaccines, HPV vaccines, and hepatitis B vaccine.

Several booster shots may be needed.

New types of vaccines
A number of new types of vaccines are being developed. A vaccine to protect against multiple diseases caused by mosquitos is being developed to cause an immune response to mosquitos saliva rather than a particular virus or bacterium.

Publications

 * 2018, Do Vaccines Cause Fibromyalgia or Chronic Fatigue Syndrome (CFS)? in The Clinician’s Vaccine Safety Resource Guide

Learn more

 * Vaccine Basics - Health and Human Services
 * Vaccine Types - NIAID
 * Coronavirus (COVID-19) vaccines - World Health Organization - with a details of vaccines in development
 * Vaccine Storage and Handling - CDC
 * 10 Things to Know about US COVID-19 Vaccine Plans
 * Vaccines Video short - Blausen.com