The Viral Theory Gains Popularity in 1970-80s
Chess’ research, in which rubella virus was suspected to cause autism triggered the development of a new approach in the field: the search for roots of autism.
Some viral agents present in children with autism were studied. The studies tested the experience of viral exposure in the prenatal period. As a result, it was shown in 1977-80 that rubella, measles, mumps, and cytomegalovirus infections during pregnancy were associated with ASD incidence in a child.
The common characteristics of these viruses are that they are “slow viruses” as they were called then. Now we refer to such infections as chronic/latent. This means that the infection’s course is not acute, it does not cause visible inflammation, but it persists in a body for a long time, disrupting the immune system functions.
Further, it was hypothesized that prenatal exposure to viral agents that may potentially affect brain development and cause some alterations in the immune system of ASD children.
As a result, in 1978-82, several studies aiming at the cellular immunity status were conducted. The hypothesis was confirmed: multiple severe immune systems and blood cell count alterations were detected in ASD children. At this time, most of the scientific community was convinced that there is an infectious etiology of ASD, so some treatments targeted at the immune system recovery and inhibition of viruses were tested.
For example, transfer factor immunotherapy was tried. The idea of this method is to transfer antibodies to a virus from donor to an ASD child, so that his immune system could handle the viral exposure and to inhibit it. After administration of antibodies from a donor, the children showed pronounced improvements in motor and social communication skills, indicating that the root cause is affected. However, this type of therapy is not the most effective against viral infections, so the results were not outstanding.
Nevertheless, in that time in the publications, the authors stated that although the etiology of ASD is unknown, most likely it is a prenatal intrauterine infection, while nowadays it is stated that etiology is unknown, but most likely it is a combination of genetic and environmental factors (which may include anything).