What are adverse events?

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Adverse events can be a relatively undescriptive term. It could mean the common side-effects of a vaccines such as a temporary headache, fever, or muscle aches. It could mean the serious adverse events such as allergic reaction.

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Let's cover the mild effects first, and clear up a common misconception. From the CDC:

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"Some people report having mild side effects after flu vaccination. The most common side effects from flu shots are soreness, redness, tenderness or swelling where the shot was given. Low-grade fever, headache and muscle aches also may occur. If these reactions occur, they usually begin soon after vaccination and last 1-2 days."

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It's easy to see why people might be inclined to think that the flu vaccine gives you the flu. You might develop flu-like symptoms, which is simply your body's immune response creating immunity against the flu virus. You can read about it on the Seattle Children's website.

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Some vaccines, however, do utilise a weakened version of the actual virus to essentially infect you on easy mode so your immune system can easily develop immunity and combat the virus. There are the anomilies who are immunocompromised who can't fight off this weakened virus. It's sad and heart-breaking, but this isn't typical.

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In the interest of fairness and transparency, here's a story of just this very thing. These things are incredibly microscopically rare, and it depends on the vaccine. While these things do happen, we can't fabricate reality and make it seem like it happens more than it does.

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"That was a known risk of the vaccination, which causes roughly one case of the disease per 2.4 million doses, often in people with an immune deficiency. A safer, inactivated, polio vaccine was available at the time, but the oral vaccine was cheaper, easier to administer"

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"But tragically, Salamone found out first-hand that vaccines do have real, rare side effects when he saw his infant son, David, become weak and unable to crawl shortly after receiving the oral polio vaccine in 1990. After about two years of physical therapy and doctors' visits, Salamone learned that owing to a weakened immune system, David had contracted polio from the vaccine. "We basically gave him polio that day,""

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Adverse events going forward

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For the sake of this page, we're going to only focus on the serious adverse events. This means anything such as:
-Allergic reactions

-Seizures

-Severe virus-like symptoms

-Death

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So let's start with something easy to cover that's readily available: what is the adverse event rate for various vaccines?

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Starting off with some classification. Not all adverse events are attributed to the vaccine in question. There are three terms to be aware of as reported by the WHO.

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Observed rate - This is the total number of health complications reports in vaccinated people

Vaccine reaction rate - This is the number of health complications in vaccinated people which are atrributed to the vaccine

Background rate - This is the number of health complications in vaccinated people which are not attributed to the vaccine

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Background rate events would probably have happened anyway, and could very well just be a coinsidental occurance.

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Let's look at severe adverse event rates

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Vaccine Serious Adverse Reaction Information

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This is taken from the WHO's database which you can download the PDF for, for each individual vaccine.

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----------Anthrax Vaccine----------

"The rate of anaphylaxis is reported to be 0.76 episodes per 100,000 doses"

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"A case of hypersensitivity pneumonitis following anthrax vaccination has been described (Timmer et al., 2002). Marano et al. (2008) listed 9 severeadverse events involving 7 participants out of 1,005 enrollees in the study as possiblyassociated with AVA, but the complete unblinded analysis of such events is not yet available"

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"following AVA administered to 500,000 US military personnel that included individual case review, there was no evidence for an unusual reporting rate of any severeor unusual adverse events"

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So the numbers are 0.76 cases per 100,000 people (0.0000076%), possibly 7 out of 1,005 (0.0069%), and 0 in 500,000 (0%).

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----------BCG Vaccine----------

Osteitis and Osteomyelitis -"35 per million in Czechoslovakia after a shift from the Prague to Russian strain BCG"

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"Sweden reported rates as high as 1 in 3,000 vaccine recipients, which declined rapidly when the national programme shifted to a Danish (Copenhagen,1331) vaccine strain"

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Disseminated BCG disease or systemic BCG-itis:

"The risk (fatal and non-fatal) is thought to be between 1.56 and 4.29 cases per million doses"

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"Additional data from studies in South Africa confirm the significantly high risk of disseminated BCG (dBCG) disease in HIV-positive infants, with rates approaching 1%"

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So we have 35 in 1 million when switching to a less safe version of the vaccine (0.000035%), 1 in 3000 when doing the same thing (0.00033%, and 1% for children with HIV.

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----------Diphtheria, Tetanus and Pertussis (DTP) combination Vaccines----------

"The rate of febrile seizures occurring within 3 days of DTwP vaccination has been shown to be reasonably consistent in clinical studies 60 per 100,000 doses and in active surveillance studies which have used data linkage 8 per 100,000 doses" - as a note this is more prevelent in people with a history of seizures.

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"A data linkage study showed a rate of 0.13 (CI 0.003 to 0.71) cases per 100,000 administered doses of DTwP vaccine"

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So the most I could find which could reliably say this actually happens is 60 in 100,000 (0.0006%), 8 in 100,000 (0.00008%), and 0.13 cases per 100,000 (0.0000013%).

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----------Hepatitis B Vaccine----------

"Anaphylactic reactions - The estimated incidence of anaphylaxis among vaccine recipients is 1.1 per million vaccine dose"

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There are other reactions suggested, but none meeting the standard of proof to be sure. So our number is 1.1 in 1 million (0.0000011%)

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----------Monovalent Hib Vaccine----------

"Severeadverse events following administration of Hib vaccine are uncommon, making it one of the safest vaccines currently available. In a study of >4000 infants, there were no differences in the type and frequency of severeadverse eventsoccurring among those receiving Hib conjugate vaccine and those receiving a placebo"

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So our number is essentially 0.

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----------HPV Vaccine----------

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"As at June 2017 it is estimated that over 270 million doses of the HPV vaccine have been distributed. Post-licensure surveillance data concerning the safety profiles for each of the HPV vaccine brands have detected no serious safety issues to date except rare reports of anaphylaxis."

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"This comprehensive systematic review containing a large body of high-level evidence is very consistent in finding no evidence of severe or serious adverse events associated with difference in the rate of Serious Adverse Events (SAE) between people who have received either the 2v-HPV or 4v-HPVvaccines and people who received a placebo or a control vaccine. "

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So our number is essentially 0.

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----------Influenza Vaccine----------

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Inactivated influenza vaccine - "Among those who received this vaccine, the rate of GBS that exceeded the background rate was slightly less than 10 cases per million vaccinated"

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Live attenuated influenza vaccine - "Their report included 7 reports of anaphylaxis which provides an estimated rate of anaphylaxis of 1 per 500,000 doses."

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So our numbers are 10 in 1,000,000 (0.00001%) and 1 per 500,000 (0.000002%).

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----------Japanese encephalitis Vaccines----------

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Inactivated Vero cell-derived vaccine  - "In clinical trials in adults and children, no serious adverse events related to vaccination have been reported."

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"An increased risk of neurological events has not been reported with this vaccine"

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Inactivated mouse brain-derived vaccine - "Hypersensitivity reactions, including serious generalized urticaria, facial angio-oedema or respiratory distress, have been reported (18–64 per 10,000 vaccinees)".

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"In Japanese children, systemic immediate-type reactions occurred with a frequency of 1 to 2 per million doses"

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"Up to one case of acute disseminated encephalomyelitis (ADEM) per million vaccinees has been reported in Japan (Monath, 2002; Tsai et al., 1999). In Denmark, between 1983 and 1995, this rate reached 1 per 50,000 – 75,000 vaccinees for reasons not yet fully understood"

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"Only one fatal case (8-year old boy with a complex congenital heart condition), was noted during surveillance of more than 10 million doses administered in Japan and the US (Takahashi et al., 2000). Neurological complications including encephalitis, encephalopathy, convulsions, peripheral neuropathy, transverse myelitis and aseptic meningitis have been very rarely reported in Japanese children, with an incidence of 1 per million vaccinees"

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Live attenuated vaccine - "In recent clinical trials in children, two cases of pyrexia (1.5%) were reported as systemic adverse events (Kim and Houillon, 2013). No increased risk of allergic reactions were reported with this vaccine"

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Live recombinant vaccine - "No subject enrolled in clinical trials experienced allergic reactions."

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Vaccine-associated JE - "No cases of vaccine-associated disease were reported in a review of data covering a 20 year period that was presented to the GACVS in 2005 (WHO 2005)"

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So our numbers here are 0, up to 64 in 10,000 (0.0064%), up to 2 per 1,000,000 (0.000002%), 1 in 1,000,000 (0.000001%), 1 in up to 50,000 (0.00002%), one death in 10+ million ( < 0.0000001%), 1 in 1,000,000 (0.000001%), 0, 0, 0.

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----------MMR Vaccine----------

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Measles

"The rate of anaphylaxis has been documented to be variable with a rate of 3.5 to 10 per million doses of following a measles-containing vaccine"
"The risk of thrombocytopenia following MMR vaccination is 1 in 30000 to 1 in 40000 vaccinated children"

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Mumps

"In the United States, a 10-year retrospective study of hospitalized cases found only one case of aseptic meningitis per 100 000 doses"

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"Another study found 1 per 1.8 million doses administered (Nalin, 1992). In yet another study, it was associated with 1 case per million doses (Fescharek et al. 1990). It is such a rare eventthat when it does occur in association with the vaccine administration, it probably represents a coincidental occurrence."

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"In Slovenia, passive surveillance over the period 1979-85 identified 20-100 cases of aseptic meningitis per 100 000 doses of MM vaccine containing Leningrad-3 strain"

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(Leningrad-Zagreb strain) - "An incidence rate of 1.4 –4.2 per 100 000 population was observed during the peak week of the outbreak,". "A rate of 20 per 100 000 doses was recorded in Slovenia". "In Croatia 90 cases per 100 000 doses were reported"

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(Urabe strain) - "A study in Nottingham, UK, showed 9 cases of aseptic meningitis per 100 000 doses (Miller et al., 1993, Miller E et al 2007). As a result, the product was no longer purchased by UK. A Japanese study demonstrated a rate of 49 cases of aseptic meningitis per 100 000 doses of Urabe strain produced locally (Sugiura et al., 1991). A subsequent study put the rateat 100 cases per 100 000 doses"

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Rubella

"Rubella vaccines, in adults, may be associated with acute joint symptoms. Transient joint pain develops in up to 25% of post-pubertal females"

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"In a randomised placebo-controlled, double-blind study of rubella vaccination in sero-negative women there was a significantly higher incidence (p = 0.006; odds ratio = 1.73 [95% CI = 1.17-2.57]) of acute joint manifestations in rubella-vaccine recipients (n=270) compared with placebo recipients (n=276) (Tingle et al 1997)."

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"Approximately 85% of pregnancies will be negatively affected when rubella infection occurs during the first trimester. Studies on administration of rubella vaccine unknowingly during pregnancy in 6 countries showed an absence of risk of CRS associated with administering rubella vaccine shortly before or during pregnancy"

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MMRV

"The final results of the two post-licensure studies indicated that among children aged 12–23 months, one additional febrile seizure occurred 5–12 days after vaccination per 2,300–2,600 children"

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"The company initiated study among 12–60 months old (99% of whom were aged 12–23 months) showed that 5–12 days after vaccination, the rate of febrile seizures was 7.0 per 10,000 vaccinations (MMRV) and 3.2 per 10,000 vaccinations (MMR &V) respectively."

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Numbers for MMR and MMRV

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This was a long one, but our numbers are 3.5 per 10,000,000 (0.00000035%), up to 1 in 30,000 (0.00033%), 1 in 100,000 (0.000001%), 1 in 1.8 million (0.00000055), 1 in 1 million (0.000001%).

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For specific and less safe strains of vaccines the numbers are up to 100 cases per 100,000 (0.001%), up to 4.2 per 100,000 (0.000042%),  20 per 100,000 (0.0002%), 90 per 100,000 (0.0009%), 9 per 100,000 (0.00009%), 49 per 100,000 (0.00049%), and 100 per 100,000(0.001%).

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For MMRV, the numbers are 1 in up to 2300 (0.00043%), 7 per 10,000 (0.0007%), and 3.2 per 10,000 (0.00032%).

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The most substantial percentage is transient joint pain in 25% of post-puberty females. Transient = short-term. Considering that 85% of pregnancies would be negatively affected by a Rubella infection, this seems like a much better option. Additionally, the Rubella vaccination has no association between the vaccine and CRS.

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----------Pneumococcal Vaccine----------

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"No neurological disorders (e.g. Guillain–Barré syndrome) have been reliably associated with administration of pneumococcal vaccine."

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"In this same study of 19,922 vaccine recipients and 19914 subjects who received a placebo vaccine hospitalisation for viral-associated pneumonia within 8 days of vaccination (in non-HIV infected children) was more frequent (30 vs. 15 cases, P=0.03)"

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So the numbers here are 0, and extrpolating the ratio out from the second section: it's roughly 0.0015% but that's not a solid calculation.

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----------Polio Vaccine----------

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Oral Polio Vaccine

"Despite its many advantages, OPV carries the risk of vaccine-associated paralytic poliomyelitis (VAPP) particularly among infants who receivethe vaccine for the first time and their contacts. In addition, when polio vaccine coverage is low in the population, this live attenuated vaccine may revert its virulence and transmissibility and pose additional risk for emergence of vaccine-derived polioviruses (VDPVs), which have been associated with outbreaks. Because of these risks, OPV use will be discontinued worldwide once the goal of eradicating all wild poliovirus (WPV transmission) is achieved." - Just scroll up and check out the link to the story of this very thing. It's a shame.

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"The rate of VAPP is higher for the first dose of OPV than for subsequent doses, ranging from one case per 700,000 to one case per 3.4 million first doses. The risk of VAPP among first dose recipients was estimated as 1 case per 2.8 million children in India compared with first dose recipient risk of 1 case per 1.4 million children in the United States"

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"WHO estimates VAPP risk at 2-4 cases per million birth cohort. VAPP is more common in individuals who are immunocompromised. No study has demonstrated transmission from a VAPP case resulting in another VAPP case"

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"On rare occasions, particularly in immunodeficient infants, aseptic meningitis and encephalitis have been reported after OPV"

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"OPV can be administered with other vaccines, with no evidence of increased rates of adverse events nor reduced immunogenicity. OPV is frequently administered simultaneously with diphtheria–tetanus–pertussis (DPT) vaccines and therefore side effects from the latter may often be falsely attributed to OPV."

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"Some studies tried to investigate possible causation between the receipt of polio vaccine andthe development of tumours (Dittmann, 1992). Long-term follow-up studies do not support such an association"

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"On very rare occasions, the live, attenuated vaccine-virus can -over time and prolonged replication -genetically change. A vaccine-derived poliovirus (VDPV) is a live, attenuated strain of the virus contained in OPV, which has changed and reverted to a form that may be able to cause paralysis in humans and may develop the capacity for sustained circulation"

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Inactivated Poliovirus Vaccine - "Some formulations of IPV contain small amounts of streptomycin, polymyxin B and neomycin, which can theoretically cause reactions in persons allergic to these antibiotics –but no confirmation of such reactions has been found in post-marketing surveillance (Plotkin et al., 1999; CDC, 1997). No reports of anaphylaxis, thrombocytopenia or transverse myelitis (Stratton et al., 1994) after IPV have been published."

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Our numbers aren't set in stone, but the range is from 2 per 1,000,000 (0.000002%), up to 4 per 1,000,000 (0.000004%). The reactions from the oral vaccine are seemingly from people with compromised immune systems.

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----------Rabies Vaccine----------

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Nerve Tissue Vaccines

Neurological - "The incidence of these reactions varies widely from 0.0017 per 100 to 0.44 per 100". "In the best surveys conducted among large numbers of patients in one institution in charge of post-exposure treatment, complications varied from 0.1 per 1,000 to 7 per 1,000 vaccinees with a case fatality rate of up to 10%. In case of Landry paralysis, thecase fatality rate could reach 30% (Bahri et al., 1996). The Fuenzalida-type vaccine was associated with neurological complications in about 0.12 per 1,000 to 0.037 per 1000 courses"

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Cell Culture Vaccines and Embryonated egg-based Vaccines

"Neurological –At least five cases of central nervous system disease, including transient neuroparalytic illness of Guillain–Barré type, have been reported among the millions of individuals given HDCV (Bernard et al., 1982; Boe & Nyland, 1980; Knittel et al., 1989; Tornatore & Richert, 1990; Moulignier et al., 1991). This rate may not be an increase above the background rate of about 1 per 100,000 per year "

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Immunological - "A rarer immune complex-like reaction (characterized by urticaria and sometimes including arthralgia, angioedema, nausea, vomiting, fever and malaise) has been noted in approximately 6 per 100 vaccinees receiving booster doses of HDCV. This reaction was less common in persons undergoing primary immunization (WHO 2002; Dreesen, 1986). In no case have these reactions been life-threatening."

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So our numbers here are: up to 0.4 per 100 (0.004%), up to 7 per 1,000 (0.0007%), 5 in millions ( < 0.0000025% or may not be a result of the vaccine). While not exactly what I meant by severe, vomiting, fever etc was present in 6 of 100 cases for the booster (0.6%).

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----------Rotavirus Vaccine----------

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"A comprehensive systematic review containing a large body of high-certainty evidence consistently found no difference in the rate of serious adverse events (SAE) between people who have received either Rotarix, RotaTeq, Rotavac, or Rotasiilrotavirus vaccines and people who received a placebo or no intervention."

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So that's a 0.

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----------Typhoid Vaccine----------

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Oral Vaccine

"No serious adverse events have been reported for the Ty21a oral typhoid vaccine"

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Parenteral Vaccines

"No serious adverse events have been reported following ViCPS, the combined ViCPS/hepatitis A or Vi-rEPA typhoid vaccines"

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That's a 0.

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----------Varicella Zoster Virus Vaccine----------

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Post-licensure surveillance data

"No severe adverse events were associated with vaccination, including ataxia or encephalitis that are recognized complications of natural varicella. "

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Combination varicella vaccines –MMRV

"This initial evaluation has demonstrated that a rate of febrile seizure of nine per 10,000 vaccinations among MMRV vaccine recipients"

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So our numbers here are 0, and 9 in 10,000 (0.0009%).