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Historical Vaccine-Associated Incidents


René F. Najera, DrPH

March 21, 2023

No product in the known universe is 100% safe or 100% effective. There is just no perfection when it comes to anything we buy and consume. Even something as simple as drinking tap water comes with some risk, be it from environmental contamination, from old pipes leaking heavy metals into it, or from accidentally inhaling the water instead of drinking it. What matters when it comes to the safety of a product is the size and probability of the risk incurred in using the product.

For example, according to the Centers for Disease Control and Prevention (CDC), . For all children ages 1 to 18, . Nevertheless, thousands of parents and caregivers sign up their children to learn to swim, to go to pool parties, or they have a pool on their property where they cool off in the hot summer days. .

On the other hand, something relatively safe, like traveling by airplane, gives many people a feeling of uneasiness when they lift off or there is turbulence. About 3% of the population fears flying to the point where they will avoid airplanes altogether, and . Yet, from 2000 to 2022, , translating to less than 1 fatal accident per 10,000,000 departures. And, even if a particular accident is fatal, with at least one passenger dying, an individual’s risk of dying in a particular accident is less because of the safety requirements of airplanes and their crew in the United States (and other countries).

This all brings us back to vaccines, because vaccines are collectively safe, but they elicit a reaction of fear in some people. Alternatively, deadly diseases that are vaccine-preventable are met with indifference by other people, . According to an investigation by The New York Times, since the inception of the National Vaccine Injury Compensation Program in 1985, . Comparing a vaccine to the disease it prevents gives a better picture of the difference in risk. According to the Times: “The likelihood of serious harm if a person contracts measles is much greater than the chance of being injured from the measles vaccine, data shows. About one of four people who get measles are likely to be hospitalized, and one to two of every 1,000 people who get it are likely to die from the disease, according to the C.D.C. In comparison, claims of harm have been filed for about two out of every million doses of the measles vaccine.”

However, 6,600 is not equal to zero. (Though that number is not millions, either.) But vaccines are getting safer and safer with the passage of time, as scientists and vaccine manufacturers learn from previous experiences and refine their formulations. Or as public health authorities look at the epidemiology of both the disease and the vaccine injuries, and .

Still, when one incident related to a vaccine accident or injury is reported by the media and amplified through social media, the results can be significant. For example, in Samoa in 2018, a vial of MMR (measles, mumps and rubella) vaccine was not properly prepared. . Two children were killed in the accident, and the nurses were sentenced to prison time for manslaughter. The public did not trust the vaccine, and the rate of MMR vaccine coverage dropped. A year later, an epidemic of measles went through the island nation, sickening over 5,700 people (mostly children) and killing 83. (According to reports, .) Even as the deaths piled up in Samoa, , telling people to forgo the vaccine and try “natural” remedies instead.

That incident in Samoa was not the first or last situation where something relatively rare scares people away from vaccination and into the waiting arms of anti-vaccination movements. Below are some historical examples of accidents and incidents associated with vaccines. In their time, these incidents eroded the public trust of vaccinations, a trust that had to be regained over time, with serious consequences for the children left unprotected as their parents were scared away from vaccination.

  • 1901 Diphtheria Antitoxin Contaminated With Tetanus
    • In the late 1800s and early 1900s, the antitoxin was the only treatment available to treat diphtheria, a bacterial infection of the respiratory tract. The antitoxin was created by injecting diphtheria toxin into horses, then drawing blood from the horses to harvest the antibodies against the toxin. Those antibodies were the basis of the antitoxin and given to children. One such horse (named “Jim”) contracted tetanus and died from it. The serum taken from the horse was not tested for tetanus and used in the preparation of several batches of diphtheria antitoxin. As a result, . They would not be the last...
  • 1901 Smallpox Vaccine Contaminated With Tetanus 
    • An incident similar to what happened in St. Louis , also in 1901. In this case, it was a vaccine batch contaminated with . Nine children died in this second accident, and it became clear that more stringent regulation of medicine manufacturing was necessary. The result was the , a law that would evolve and lead to the creation of the Food and Drug Administration.
  • 1902 Plague Vaccine Contaminated with Tetanus in Mulowali, India
    • In the late 1800s and early 1900s, plague (Yersinia pestis) affected the Indian subcontinent. A scientist named Waldemar Haffkine arrived there to work with the British government (India was colonized by the British at the time) and create a vaccine against plague. In 1897, after first trying the vaccine on himself, . Another 172 were left without treatment as a comparison group. Those who received the vaccine were six times less likely to be ill, and had no deaths, compared to six deaths in the untreated. The vaccine was a success and went into mass production. In 1902, nineteen people died of tetanus after receiving Haffkine’s vaccine. Contamination similar to what was seen in the United States was suspected, and
  • 1928 Diphtheria Vaccine Contaminated with S. aureus in Bundaberg, Australia
    • Known as the “Bundaberg Tragedy,” this incident happened in 1928 in Australia. Unlike previous “vaccines” against diphtheria, which were antitoxins (antibodies made by a horse or cow against a toxin), the diphtheria vaccine was an inactivated toxin (toxoid) vaccine, where the people receiving the vaccine made the antibodies against the toxin themselves. Just like previous accidents, . Twelve children died from toxicity from bacterial contamination in 36 hours, overwhelming the local healthcare system. Several other children were critically ill.
  • 1932 BCG Vaccine Against Tuberculosis with Live M. tuberculosis in Lübek, Germany
    • The Bacille Calmette–Guérin (BCG) vaccine has been used for almost 100 years to prevent systemic tuberculosis in children in developing nations. In 1929, 412 children in Germany were given the BCG vaccine as part of routine immunization. The laboratory where the vaccine was made also grew live cultures of Mycobacterium tuberculosis, and . Initial concerns were that the vaccine had “reverted” into a virulent strain of M. tuberculosis. Subsequent investigations showed that the strain in those vaccines was not the processed one, but a fully live one capable of causing disease, and that it came from laboratory contamination. The epidemiological study made the consequences of the contamination clear:
      “Among the 251 inoculated children, 228 (90.8%) developed some clinical or radiographic evidence of TB disease (Table 1), and 77 infants (30.7% of those inoculated) died within a year of inoculation. Of those who died, five were thought to have died of TB-unrelated causes, while the remaining 72 demonstrated clinical evidence of extensive TB. While the parents of four of the children refused permission for autopsy, pathology on autopsies of all remaining 68 children confirmed the clinical diagnosis of TB disease [11]. In contrast, of the 164 non-inoculated children born during the same period, 19 (11.6%) died before the age of three, including 16 before the age of one, from TB-unrelated causes. We calculated that mortality in the first year of life was 3.1 (95% CI 1.9–5.1) times higher in inoculated than non-inoculated children. Male children were more likely to die during follow-up than females (relative risk [RR] 1.6, 95% CI 1.0–2.3) (S1 Table). Of note, the proportion at year one of non-TB–related deaths in the inoculated children was significantly reduced compared to non-inoculated neonates (p = 0.002).”
  • 1955 Polio Vaccine Not Properly Inactivated (“Cutter Incident”) in the United States
    • In 1955, when the Salk vaccine was approved for wide use after , batches of the vaccine produced by Cutter Laboratories in California had active virus, instead of the killed virus preparation of the Salk vaccine. Vaccines from those batches were given to about 120,000 children, and about 40,000 of those children developed “abortive” polio, . Fifty-six children were reported to have paralytic polio after receiving the vaccine from Cutter Laboratories, with five dying. . This incident lowered confidence in the Salk polio vaccine, and the Sabin oral polio vaccine (OPV) replaced the inactivated vaccine in the early 1960s. The inactivated polio vaccine (IPV) returned to the vaccination schedules in the United States and other developed nations in the 1980s, and continues to replace the OPV in nations where polio is eliminated.
  • 1955 to 1963 A Simian Virus in Polio Vaccines in the United States 
    • According to CDC, “(f)rom 1955 to 1963, an estimated 10-30% of polio vaccines administered in the US were contaminated with simian virus 40 (SV40).” The contamination happened when monkey kidney cells used to grow the virus were found to have the virus from a natural infection in the donor monkeys. Once this contamination was found, the quality control process was changed so that the virus is no longer found in vaccines. Nevertheless, the virus is known to cause cancer in some animals, and . However, multiple studies have looked at the association between cancer in humans and SV40 infection through polio vaccination, and the Institute of Medicine concluded the following:
      “There have been many questions as to the effects on people who received the contaminated vaccine. SV40 has biological properties consistent with a cancer-causing virus, but researchers have not conclusively established whether or not it could cause cancer in humans. Studies of groups of people who received polio vaccine during 1955–1963 provide evidence of no increased cancer risk. However, because these epidemiologic studies are sufficiently flawed, the Institute of Medicine's Immunization Safety Review Committee concluded that the evidence was inadequate to conclude whether or not the contaminated polio vaccine caused cancer.”
  • 1976 Swine Flu Vaccine and Guillain-Barré Syndrome in the United States
    • In early 1976, a soldier at Fort Dix in New Jersey died of influenza type A (H1N1), also known as “swine flu,” during an outbreak of the disease at the barracks. Fearing a return of the strain of influenza that caused the 1918 pandemic, . Congress and President Gerald Ford agreed to fund and promote vaccination efforts. The large epidemic did not come to pass. What did happen was an observed increase in the risk of (GBS), a neurological condition resulting from an autoimmune destruction of the nerves in the arms and legs. In the United States, the incidence of GBS is one per 100,000 residents. Among those vaccinated in the 1976 vaccine push, the incidence was higher than in the general population, leading to a shutdown of the vaccination effort by December. During the vaccination campaign, about 48 million people received the vaccine in the United States. Of those, .
  • 1980 Smallpox Vaccine Overdose in a Child in Venezuela
    • In the waning days of smallpox vaccination, a child in Venezuela who was supposed to get their measles vaccine received 25 doses of smallpox vaccination, all at once by accident. The accident was discovered early, and the child was given the antiviral medication methisazone. Four days after the accident, the child developed a fever, and the site of the injection developed a bump. On day 5, the child was given antibodies against the vaccinia virus (the virus used in the smallpox vaccination). The symptoms resolved on the eighth day after the accident, and the child was medically cleared on day twelve.
      You can read the report of this incident here:  
  • 1998 RotaShield Rotavirus Vaccine Associated With an Increased Risk of Intussusception
    • The rotavirus vaccine was licensed in 1998. Soon after the vaccine was administered to many children, healthcare providers filed reports of intussusception. After an investigation, it was determined that the children who received the vaccine had an increased risk of intussusception, a condition where the intestine folds into itself like a telescope. validated the increased risk concerns, leading to the withdrawal of the vaccine from the marker. (It should be noted that intussusception is a risk of acquiring rotavirus infection, hence the recommendation for the rotavirus vaccines that came later.)
  • 2002 Lyme Vaccine Withdrawn from Market
    • A vaccine against Lyme disease () was licensed in 1998. The three-dose vaccine had up to 80% effectiveness in clinical trials. Three years later, . Increased media attention to people reporting adverse events and led to the withdrawal of the vaccine. However, epidemiological and biostatistical analysis of the data revealed that the rate of serious adverse events like joint pain, neurological deficits, hospitalization or death, was no different than what is expected in the population at large from other causes. According to : “On 9 July 2003 [GlaxoSmithKilne] . The final agreement included over 1 million dollars in legal fees for the prosecuting lawyers, but provided no financial compensation to the ‘vaccine victims’. The plaintiffs’ attorneys stated that the voluntary removal of LYMErix™ from the market accomplished the main goal of the suit. Despite the settlement, the manufacturer continued to deny that LYMErix™ caused harm and indicated that the decision to settle represented a choice based on economic concerns (i.e. the desire to avoid the costs of lengthy litigation) for a product showing relatively poor performance in the market.”
  • 2010 Porcine circovirus DNA detected in Rotavirus Vaccines
    • Animal tissues and other products are used in the creation of many vaccines. Some of those products have been known to be contaminated with animal viruses (see the entry above on SV40). In 2010, the makers of the Rotatrix® vaccine confirmed that DNA from a porcine (pig-related) virus called a “circovirus” was present in the vaccine. Soon after, . The DNA was present, but viable circovirus was not, probably because it was destroyed in the process of making the vaccine. While the circovirus DNA was detected in stool samples of some children who received the vaccine, those same children “” to the virus, signaling a lack of infection with the virus. Nevertheless, the Food and Drug Administration (FDA) suspended the administration of the vaccines in the United States out of an abundance of caution, while more studies were conducted. Three months later, after studying the evidence for and against continued vaccination and input from the manufacturers on their remediation plans, the FDA recommended the continuation of the rotavirus vaccination plans in the United States.  : “It’s not at all clear that the presence of porcine circovirus 1 DNA in Rotarix is a problem. Circoviruses have not been associated with human disease, and porcine circovirus 1 has not been found to cause disease in any animal. Many humans have antibodies to these viruses, including porcine circovirus, indicating that they were infected at one time. Furthermore, it’s not known if the vaccine contains infectious virus or DNA fragments. Nevertheless, it’s always preferable to err on the side of caution, as the FDA has done.”
  • 2015 Contaminated Hepatitis B Vaccine Causes Severe Reactions and Deaths in Chiapas, Mexico
    • after receiving a dose of the hepatitis B vaccine in a vaccination clinic in Chiapas, Mexico. Public Health authorities investigating the incident . Subsequent investigations showed , as the bacteria was recovered from cultures of the infants.
  • 2018 Anesthetic Used Instead of Diluent in Samoa
    • A vial of MMR (measles, mumps and rubella) vaccine was not properly prepared.. Two children were killed in the accident, and the nurses were sentenced to prison time for manslaughter. The public did not trust the vaccine, and the rate of MMR vaccine coverage dropped. A year later, an epidemic of measles went through the island nation, sickening over 5,700 people (mostly children) and killing 83. (According to reports,.)
  • 2018 Ineffective Vaccines Given to Thousands of Children in China
    • An inspection of a biotechnology manufacturing plant by the Chinese Government unveiled discrepancies in the quality control of rabies and DPT (diphtheria, pertussis, tetanus) vaccines, . An investigation revealed , which was prompted by a whistleblower report. As a result, hundreds of thousands of doses of the vaccines were recalled, and .


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