Relatively common adverse effects of immunization include high fever and fits. Other symptoms and death have also been linked to vaccinations. Often the symptoms are milder versions of the disease against which the vaccine is administered.
The Centers for Disease Control and Prevention and the U.S. Food and Drug Administration maintain a database of information about adverse effects from the administration of vaccines licensed in the U.S. The database is called the Vaccine Adverse Event Reporting System (VAERS), a program created under the National Childhood Vaccine Injury Act of 1986. Reporting is voluntary. Vaccine manufacturers are shielded by the US Government from civil liability from any vaccine-related injuries. Reports sow that that between 2,500 and 3,000 children are killed or injured each year by vaccines.
Meningitis was reported after several types of vaccinations. One study, published in the journal Neurology, evaluated data from the US Vaccine Adverse Event Reporting System (VAERS) to look at the rate of occurrence of meningitis after any vaccination during the period 1990 to 2010. The study group comprised individuals from infancy to 74.7 years; the period considered the onset of meningitis within six weeks after an individual was vaccinated. Of the 722 cases found, 415 (57.5%) occurred in the first six weeks and 327 (45.2%) occurred within the first two weeks. In the group, 76% of the individuals were hospitalized and 6.9% were disabled after the infection cleared.
Overdoses of vaccines against the following diseases can cause medical complications: BCG, typhoid, paratyphoid, cholera, plague, tetanus, diphtheria, pertussis, smallpox, rabies, typhus, yellow fever, measles, poliomyelitis and various viruses.
The measles-mumps-rubella (MMR) vaccine can cause a rare bleeding disorder called idiopathic thrombocytopenic purpura (ITP). The reaction, caused by the destruction of the platelets that help blood clot, seems to occur most often within the first 2 or 3 weeks of receipt of the vaccine. The resulting thrombocytopenia is described as transient and benign. In the UK, the absolute risk (of hospitalization for ITP) within six weeks of immunization was assessed as 1 in 22,300 doses. It is noted that ITP can also occur in children following a viral infection, such as measles, rubella or mumps. For instance, one case of ITP occurs for about every 3000 rubella infections.
Research reported in 1994 into adverse reactions to MMR (measles, mumps, rubella) and DPT (or DTP: diphtheria, tetanus, whooping cough/whooping cough) vaccinations by the Centers for Disease Control and Prevention (USA) identified 34 major side effects, including asthma, blood disorders, infectious diseases, diabetes and neurological disorders (polio, meningitis, hearing loss and others). There have also been reports of cot deaths linked to the DPT shot and asthma, allergies and arthritis to the rubella injection. Reactions to DPT vaccination were immediate whilst the worst reactions to the MMR vaccine came between eight days and two weeks after the injection. The most significant finding was the increase in the rate of seizures, which rose to three times above the national norm within the first day of a child receiving either a DPT or MMR injection. Research pointed to aluminium adjuvants -- which can trigger an immunological storm of events and cascades of immune activity far from the injection site, including cytokines (inflammatory proteins with names such as interleukin-1beta and interleukin-6 -- that have been found at significantly higher levels in autistic patients than healthy controls. This evidence adds to a growing, current body of research that autism is, at root, a disease of a dysfunctional and hyper-stimulated immune system. The US Government has paid vaccine damage compensation to some parents of autistic children.
The original DTP vaccine contained Thimerosal or Merthiolate, a neurotoxic organomercury compound, and was discontinued in the West after numerous lawsuits in the 1980s won large damage awards on behalf of brain-damaged children; a safer, acellular version became available in 1991. However, the "original" vaccine continues to be produced and administered in Africa by a public-private partnership of organisations such as CEPI, (Coalition for Epidemic Preparedness) and GAVI, (Global Alliance for Vaccines and Immunizations) and with the official blessing of World Health Organization (WHO). A 2017 Danish government commissioned study of all-cause mortality in a large group of children from Guinea-Bissau, half of whom were vaccinated with DTP and half were not, found that after just one dose at three months of age, the vaccinated children died at ten times the rate of the unvaccinated from a wide range of diseases, including pneumonia, anemia, malaria and dysentery; it concluded that the vaccine had indeed protected them against diphtheria, tetanus and whooping cough, but destroyed their immune systems in the process, rendering them much more vulnerable to the major diseases of their area.
In 2001, The US Food and Drug Administration were investigating more than 100 people whose arthritis or joint pain (symptoms of Lyme Disease) were possibly linked to their vaccination against the Lyme disease. Aluminium oxyhydroxide is a commonly used adjuvant in the vaccine.
The French Government abandoned its hepatitis B vaccine programme for children after more than 15,000 lawsuits were filed for brain damage and other serious health problems.