Vaccine shedding

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Vaccine shedding is a form of viral shedding [1] [2] which can occasionally occur following a viral infection caused by an attenuated (or "live virus") vaccine. Illness in others resulting from transmission through this type of viral shedding is rare. [3] [4] Most vaccines are not attenuated (live virus) vaccines, [5] and therefore cannot cause vaccine-induced viral shedding, though the idea of shedding is a popular anti-vaccination myth. [6]

Contents

The specific use of the term "vaccine shedding" has risen to public prominence through anti-vaccine activists linked to misinformation related to COVID-19, who erroneously claim that COVID-19 vaccination can cause individuals to shed coronavirus spike protein and affect menstruation and fertility in women exposed to them. [7] [3] [8] [9] [10] However, the spike protein generated by vaccination does not shed, and there is no evidence to suggest that these vaccines cause menstruation and fertility problems. [3] [11] Vaccination also cannot cause shedding of the COVID-19 virus since none of the COVID-19 vaccines authorized for use by the FDA or the World Health Organization as of December 2021 are live-virus vaccines. [12] [13] Despite this, a COVID-19 "vaccine shedding" conspiracy theory has subsequently emerged, leading to vaccine hesitancy among some people. [3] [10] [14]

Shedding is only possible with an attenuated vaccine. It is impossible with other vaccine technologies such as inactivated vaccine (killed-virus vaccines), viral vector vaccine, RNA vaccines (that contain no virus), [14] or subunit vaccines (a vaccine technology using only isolated proteins of a virus). Only a small number of vaccines use technology that contain live virus which can theoretically infect others.

With the exception of the oral polio vaccine (OPV), there have been no documented cases of vaccine-induced viral shedding that has infected contacts of a person vaccinated with an attenuated (live-virus) vaccine. [15]

Occurrences

The only human vaccine to have caused any significant number of infections is the oral polio vaccine (OPV), [16] [6] which takes advantage of the contact immunity from shed vaccine virus to amplify the effectiveness of vaccination campaigns. [17] However, under conditions of persistent circulation in undervaccinated populations, reversion mutations that reactivate the virus can give rise to disease-causing circulating vaccine-derived poliovirus (cVDPV) strains, [18] and this vaccine is no longer used in developed countries. [16] However, the OPV is still used in Asia and Africa, leading to a small number of vaccine-induced polio infections each year. [19]

The route of infection is through contact with faeces, and some live vaccines, like the viruses they prevent, are shed in stool for up to 28 days. [20] Normal hygiene is sufficient to prevent infection among healthy individuals, [21] but immunocompromised individuals need to be especially diligent. [22]

Other attenuated vaccines show no significant viral shedding, and inadvertent infection is rare. [23] For example, only eleven cases of chickenpox transmission by vaccinated individuals have been documented out of approximately fifty million doses, [24] and but a single documented case of influenza virus transmission, and that person remained asymptomatic. [4]

The attenuated virus from vaccines is much weaker and less likely to infect than the wild virus. [25]

In dogs, vaccine-induced viral shedding has been observed with live attenuated Canine parvovirus vaccines. [26]

Research

Regulatory authorities in the US and EU recommend that shedding data should be collected both during the development phase of a new product and during clinical trials. A full report on shedding must subsequently be included in the Biologics license application. [27] [28]

A study of 345 participants aged 5–49 years who received the live influenza virus vaccine LAIV3, and for whom shedding was assessed by viral culture of nasal swabs (daily for days 1–7 post vaccination, every other day for days 9 through 25, and on day 28) indicated that 30 percent had detectable virus in nasal secretions obtained by nasal swabbing. In an open-label study of 200 children aged 6–59 months who received a single dose of LAIV3, shedding of low titers of at least one vaccine virus was detected on culture in 79 percent of children and was more common among the younger recipients. Serious illnesses have not been reported among unvaccinated persons infected inadvertently with vaccine viruses. The estimated probability of transmission of vaccine virus within a contact group with a single LAIV recipient in this population was 0.58 percent. [29]

Related Research Articles

<span class="mw-page-title-main">Polio</span> Infectious disease caused by poliovirus

Poliomyelitis, commonly shortened to polio, is an infectious disease caused by the poliovirus. Approximately 75% of cases are asymptomatic; mild symptoms which can occur include sore throat and fever; in a proportion of cases more severe symptoms develop such as headache, neck stiffness, and paresthesia. These symptoms usually pass within one or two weeks. A less common symptom is permanent paralysis, and possible death in extreme cases. Years after recovery, post-polio syndrome may occur, with a slow development of muscle weakness similar to that which the person had during the initial infection.

<span class="mw-page-title-main">Vaccine</span> Pathogen-derived preparation that provides acquired immunity to an infectious disease

A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. 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 recognize further and destroy any of the microorganisms associated with that agent that it may encounter in the future.

<span class="mw-page-title-main">Antiviral drug</span> Medication used to treat a viral infection

Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Antiviral drugs are a class of antimicrobials, a larger group which also includes antibiotic, antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from virucides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural virucides are produced by some plants such as eucalyptus and Australian tea trees.

<span class="mw-page-title-main">Polio vaccine</span> Vaccine to prevent poliomyelitis

Polio vaccines are vaccines used to prevent poliomyelitis (polio). Two types are used: an inactivated poliovirus given by injection (IPV) and a weakened poliovirus given by mouth (OPV). The World Health Organization (WHO) recommends all children be fully vaccinated against polio. The two vaccines have eliminated polio from most of the world, and reduced the number of cases reported each year from an estimated 350,000 in 1988 to 33 in 2018.

<span class="mw-page-title-main">Swine influenza</span> Infection caused by influenza viruses endemic to pigs

Swine influenza is an infection caused by any of several types of swine influenza viruses. Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) refers to any strain of the influenza family of viruses that is endemic in pigs. As of 2009, identified SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3.

<span class="mw-page-title-main">Childhood immunizations in the United States</span>

The schedule for childhood immunizations in the United States is published by the Centers for Disease Control and Prevention (CDC). The vaccination schedule is broken down by age: birth to six years of age, seven to eighteen, and adults nineteen and older. Childhood immunizations are key in preventing diseases with epidemic potential.

<span class="mw-page-title-main">Contact immunity</span> Gaining immunity due to contact with a recently vaccinated person rather than from getting a vaccine

Contact immunity is the property of some vaccines, where a vaccinated individual can confer immunity upon unimmunized individuals through contact with bodily fluids or excrement. In other words, if person “A” has been vaccinated for virus X and person “B” has not, person “B” can receive immunity to virus X just by coming into contact with person “A”. The term was coined by Romanian physician Ioan Cantacuzino.

Bovine alphaherpesvirus 1 (BoHV-1) is a virus of the family Herpesviridae and the subfamily Alphaherpesvirinae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis. BoHV-1 is also a contributing factor in shipping fever, also known as bovine respiratory disease (BRD). It is spread horizontally through sexual contact, artificial insemination, and aerosol transmission and it may also be transmitted vertically across the placenta. BoHV-1 can cause both clinical and subclinical infections, depending on the virulence of the strain. Although these symptoms are mainly non-life-threatening it is an economically important disease as infection may cause a drop in production and affect trade restrictions. Like other herpesviruses, BoHV-1 causes a lifelong latent infection and sporadic shedding of the virus. The sciatic nerve and trigeminal nerve are the sites of latency. A reactivated latent carrier is normally the source of infection in a herd. The clinical signs displayed are dependent on the virulence of the strain. There is a vaccine available which reduces the severity and incidence of disease. Some countries in Europe have successfully eradicated the disease by applying a strict culling policy.

<span class="mw-page-title-main">Booster dose</span> Additional administration of vaccine

A booster dose is an extra administration of a vaccine after an earlier (primer) dose. After initial immunization, a booster provides a re-exposure to the immunizing antigen. It is intended to increase immunity against that antigen back to protective levels after memory against that antigen has declined through time. For example, tetanus shot boosters are often recommended every 10 years, by which point memory cells specific against tetanus lose their function or undergo apoptosis.

A breakthrough infection is a case of illness in which a vaccinated individual becomes infected with the illness, because the vaccine has failed to provide complete immunity against the pathogen. Breakthrough infections have been identified in individuals immunized against a variety of diseases including mumps, varicella (Chickenpox), influenza, and COVID-19. The characteristics of the breakthrough infection are dependent on the virus itself. Often, infection of the vaccinated individual results in milder symptoms and shorter duration than if the infection were contracted naturally.

<span class="mw-page-title-main">Polio eradication</span> Effort to permanently eliminate all cases of poliomyelitis infection

Polio eradication, the permanent global cessation of circulation of the poliovirus and hence elimination of the poliomyelitis (polio) it causes, is the aim of a multinational public health effort begun in 1988, led by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF) and the Rotary Foundation. These organizations, along with the U.S. Centers for Disease Control and Prevention (CDC) and The Gates Foundation, have spearheaded the campaign through the Global Polio Eradication Initiative (GPEI). Successful eradication of infectious diseases has been achieved twice before, with smallpox in humans and rinderpest in ruminants.

Immunization during pregnancy is the administration of a vaccine to a pregnant individual. This may be done either to protect the individual from disease or to induce an antibody response, such that the antibodies cross the placenta and provide passive immunity to the infant after birth. In many countries, including the US, Canada, UK, Australia and New Zealand, vaccination against influenza, COVID-19 and whooping cough is routinely offered during pregnancy.

An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by "killing" the pathogen.

Mass vaccination is a public policy effort to vaccinate a large number of people, possibly the entire population of the world or of a country or region, within a short period of time. This policy may be directed during a pandemic, when there is a localized outbreak or scare of a disease for which a vaccine exists, or when a new vaccine is invented.

<span class="mw-page-title-main">Influenza</span> Infectious disease

Influenza, commonly known as "the flu" or just "flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin from one to four days after exposure to the virus and last for about 2–8 days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia, which can be caused by the virus or by a subsequent bacterial infection. Other complications of infection include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease.

<span class="mw-page-title-main">Inactivated vaccine</span> Vaccine using a killed version of a disease pathogen

An inactivated vaccine is a vaccine consisting of virus particles, bacteria, or other pathogens that have been grown in culture and then killed to destroy disease-producing capacity. In contrast, live vaccines use pathogens that are still alive. Pathogens for inactivated vaccines are grown under controlled conditions and are killed as a means to reduce infectivity and thus prevent infection from the vaccine.

DTaP-IPV-HepB vaccine is a combination vaccine whose generic name is diphtheria and tetanus toxoids and acellular pertussis adsorbed, hepatitis B (recombinant) and inactivated polio vaccine or DTaP-IPV-Hep B. It protects against the infectious diseases diphtheria, tetanus, pertussis, poliomyelitis, and hepatitis B.

A nasal vaccine is a vaccine administered through the nose that stimulates an immune response without an injection. It induces immunity through the inner surface of the nose, a surface that naturally comes in contact with many airborne microbes. Nasal vaccines are emerging as an alternative to injectable vaccines because they do not use needles and can be introduced through the mucosal route. Nasal vaccines can be delivered through nasal sprays to prevent respiratory infections, such as influenza.

Misinformation related to immunization and the use of vaccines circulates in mass media and social media in spite of the fact that there is no serious hesitancy or debate within mainstream medical and scientific circles about the benefits of vaccination. Unsubstantiated safety concerns related to vaccines are often presented on the internet as being scientific information. A high proportion of internet sources on the topic are "inaccurate on the whole" which can lead people searching for information to form "significant misconceptions about vaccines".

Live recombinant vaccines are biological preparations that stimulate immune responses to a pathogen through the use of genetically modified live bacteria or viruses. These live pathogens are biologically engineered to express exogenous antigens in the cytoplasm of target cells, thereby triggering immune responses. This form of vaccine combines the beneficial features of attenuated and recombinant vaccines, providing the long-lasting immunity of attenuated vaccines’ with recombinant vaccines’ genetically engineered precision and safety.

References

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  2. ↑ Lee B, Kader MA, Colgate ER, Carmolli M, Dickson DM, Diehl SA, Alam M, Afreen S, Mychaleckyj JC, Nayak U, Petri WA, Haque R, Kirkpatrick BD (2021). "Oral rotavirus vaccine shedding as a marker of mucosal immunity". Scientific Reports. Nature. 11 (1): 21760. doi:10.1038/s41598-021-01288-1. PMC   8571310 . PMID   34741103.
  3. 1 2 3 4 "Debunking the anti-vaccine hoax about 'vaccine shedding'". PolitiFact. Retrieved 2021-05-11.
  4. 1 2 Tosh PK, Boyce TG, Poland GA (January 2008). "Flu myths: dispelling the myths associated with live attenuated influenza vaccine". Mayo Clinic Proceedings. 83 (1): 77–84. doi: 10.4065/83.1.77 . ISSN   0025-6196. PMID   18174020.
  5. ↑ "Types of vaccine". Vaccine Knowledge Project. University of Oxford. Retrieved 30 December 2021.
  6. 1 2 "Vaccines: Breaking down and debunking 10 myths". USA Today. Retrieved 2018-04-29.
  7. ↑ Johansen N (2021-04-22). "Kelowna store bans anyone who has received COVID-19 vaccine". Castanet. Retrieved 2021-05-11.
  8. ↑ Hannon E (2021-04-27). "Miami Private School Informs Parents Vaccinated Teachers "May Be Transmitting Something From Their Bodies"". Slate Magazine. Retrieved 2021-05-08.
  9. ↑ Mazzei P (2021-04-26). "A private school in Miami, citing false claims, bars vaccinated teachers from contact with students". The New York Times. ISSN   0362-4331 . Retrieved 2021-05-11.
  10. 1 2 "The Latest Anti-Vax Myth: 'Vaccine Shedding'". MedPage Today. 2021-04-29. Retrieved 2021-05-11.
  11. ↑ "COVID-19 vaccines, irregular periods and spike protein shedding". Nebraska Medicine. 24 April 2021. Retrieved 30 December 2021.
  12. ↑ "Myths and Facts about COVID-19 Vaccines". Atlanta, Ga.: Centers for Disease Control and Prevention, U.S. Department of Health & Human Services. 4 October 2021.
  13. ↑ "COVID 19 Vaccine Tracker". World Health Organization. Retrieved 30 December 2021.
  14. 1 2 "No, There's Absolutely Zero Chance of 'Vaccine Shedding' From the COVID-19 Vaccines-Here's Why". Health.com. Retrieved 2021-06-07.
  15. ↑ Gregory J (13 September 2021). "The Top COVID-19 Vaccine Myths Spreading Online". Encyclopedia Britannica. NewsGuard.
  16. 1 2 "Polio Vaccine: Vaccine-Derived Poliovirus | CDC". 25 March 2021.
  17. ↑ Nathanson N, Martin J (1979). "The epidemiology of poliomyelitis: enigmas surrounding its appearance, epidemicity, and disappearance". Am J Epidemiol. 110 (6): 672–92. doi:10.1093/oxfordjournals.aje.a112848. PMID   400274.
  18. ↑ "International travel and health: Poliomyelitis (Polio)". World Health Organization (WHO). Archived from the original on 24 June 2018. Retrieved 7 July 2018.
  19. ↑ "Polio Vaccination Causes More Infections than Wild Virus".
  20. ↑ "Who Should not Get Vaccinated". www.cdc.gov. 2018-03-28. Retrieved 2018-04-29.
  21. ↑ "Ask the Experts about Rotavirus Vaccines – CDC experts answer Q&As". www.immunize.org. Retrieved 2018-04-29.
  22. ↑ Anderson EJ (October 2008). "Rotavirus vaccines: viral shedding and risk of transmission". The Lancet Infectious Diseases. 8 (10): 642–649. doi:10.1016/s1473-3099(08)70231-7. ISSN   1473-3099. PMID   18922486.
  23. ↑ King JC, Treanor J, Fast PE, Wolff M, Yan L, Iacuzio D, Readmond B, O'Brien D, Mallon K (2000-02-01). "Comparison of the Safety, Vaccine Virus Shedding, and Immunogenicity of Influenza Virus Vaccine, Trivalent, Types A and B, Live Cold-Adapted, Administered to Human Immunodeficiency Virus (HIV)-Infected and Non-HIV-Infected Adults". The Journal of Infectious Diseases. 181 (2): 725–728. doi: 10.1086/315246 . ISSN   0022-1899. PMID   10669363.
  24. ↑ "vaccine-shedding – The Immunization Partnership". www.immunizeusa.org. Archived from the original on 2018-10-07. Retrieved 2018-04-29.
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  27. ↑ "Design and Analysis of Shedding Studies for Virus or Bacteria-Based Gene Therapy and Oncolytic Products; Guidance for Industry | FDA". www.fda.gov. Retrieved 2021-01-11.
  28. ↑ Longhurst S. "Current Regulatory Thinking for Viral Shedding Studies in the European Union" (PDF). European Medicines Agency. Retrieved 11 January 2021.
  29. ↑ "Safety of Influenza Vaccines – Safety of Inactivated Influenza Vaccines (IIVs)". www.cdc.gov. 24 August 2017. Retrieved 3 February 2021.
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