In many parts of the world, including the U. The rise is probably not due to a mysterious global environmental exposure, he says. Low autism prevalence is not confined to poor countries. A handful of small studies in France, for example, have found rates around 5 cases per 10, people.
One study in Germany calculated it to be 1. Differences in scientific approach among these countries may affect the results, notes Mayada Elsabbagh , research associate at Birkbeck University of London.
Elsabbagh is working with 11 international researchers on a systematic review sponsored by the World Health Organization , including articles published in languages other than English. The report is expected to be published later this year. Language and culture may also affect the way this research is carried out. For instance, the Korean language uses an extensive array of suffixes that denote the relationship between the speaker and the subject.
Similarly, Grinker points out, healthy children from non-Western cultures may display a trait that ADOS counts as a symptom of autism. In South Korea, for example, making eye contact with an adult is not socially appropriate. Take, for instance, the theory of mind, the ability to infer what other people are thinking, which is impaired in people with autism. This linguistic reinforcement could mean that Chinese children develop theory of mind differently than do children in the West, Zaroff notes.
For example, U. In contrast, the highest recorded autism prevalence is from a study in Japan, which calculated a whopping cases per 10, people. Because of geographic and cultural isolation, Koreans are ethnically similar, which helps researchers find autism-related hotspots, says Kim, assistant professor at the Yale University Child Study Center. Because of the stigma against autism in South Korea, Kim says about half of the families declined to participate in the genetic study.
Still, the situation is gradually improving, she says. Paula C. The mRNA only stays in the outside cytoplasm , gets destroyed and never enters the inner sanctum of the nucleus. Furthermore, for the mRNA to be ever integrated into DNA, it requires a special enzyme called reverse transcriptase which humans don't have.
Pieces of spike proteins get displayed on the outside of our cells and our body makes protective antibodies that then protects us handily against the future real virus if it were ever to enter our or our children's bodies.
Unlike medications that are taken daily or periodically and can build up over time, the mRNA in the Pfizer vaccine is evanescent. It literally is just the messenger that is what the "m" in mRNA stands for and the messenger quickly disappears.
Our cells break down and destroy the mRNA within a few days after receiving the instructions to make the virus spike proteins. The presence of these fragments of the virus note this is not "live" virus prompts our immune system to generate protective antibodies to the real thing.
Our bodies break down mRNA all the time in normal cellular processes — this is nothing new. What the transience of the delivery system means is that most of the effects of the mRNA vaccines are expected to be more immediate sore arm, redness at the site, fever, chills etc. A severe allergic response has been reported to occur in some generally within the first 15 minutes, is very rare, and everyone gets observed for that as part of standard vaccine administration.
Even with the very uncommon complication of myocarditis inflammation of the heart muscle and pericarditis inflammation of the lining of the heart seen primarily in young men under the age of 30 following mRNA vaccines, these typically happen within days to 2 weeks and many return to work or school in days. In the year history of pediatric and adult vaccines , dangerous complications happen in the first two months.
There have been millions of adolescents as young as 12 years and thousands in the initial trial of children aged who have already received the vaccine and are well beyond the two-month period of observation. There is no biological reason to believe that younger children will have a different long-term side effect profile compared to adolescents or adults. Although the Pfizer trial in children aged was relatively small, it was big enough to give us statistical confidence in assessing safety and efficacy outcomes.
Scientists spend a lot of time determining the right sample size of a study during the design phase. On one hand, you want to conduct the study efficiently so that resources are used in a cost-effective way and that you get a timely answer, especially in a fast-moving pandemic.
On the other hand, you want to make sure you have enough sample size so that you can answer the question confidently as to whether the intervention works and whether there are adverse effects.
The more profound the effect size of the intervention in this case the vaccine , the fewer the numbers of children needed in the trials. Statistics help investigators determine whether the results seen would have appeared by chance or not. In this case, the effect was real and impressive. Over 3, children around the world have received the vaccines through the trials alone with no serious side effects detected. The first press release reported that the immune response in children aged was similar at one-third the vaccine dose to the response in the comparator group aged years old.
Extrapolating clinical efficacy results from immune response measurements " immunobridging " study would already have been acceptable if this was the only data. This is a standard trial design for many pediatric vaccines. Vaccines are first tested in the lab, followed by animals then adults.
Only when deemed safe in adults and various regulatory bodies have signed off, do the pediatric vaccine trials commence. Because children's immune systems and bodies are in a constant state of development, the vaccines must be right-sized. Investigators typically conduct "age de-escalation" studies in various age groups. The lowest dose is first tried so see if that is effective, then the dose is increased gradually as needed.
Immune response is the easiest, safest and most efficient way to test the efficacy of pediatric vaccines. This is a typical size and design of a childhood vaccine seeking regulatory approval. There is no reason to think that the clinical efficacy would be any different in children vs.
Although this was primarily designed as an "immunobridging" study, the initial immunologic response data was followed by real clinical outcomes in this population.
Reporting on the outcomes of 2, children in the randomized controlled trial, the vaccine was Myocarditis inflammation of the heart muscle and pericarditis inflammation of the lining of the heart have been associated with receipt of the mRNA vaccines , particularly among male adolescents and young adults, typically within a few days after receiving the second dose.
But this is very rare. For every million vaccine recipients, you would expect 41 cases in males, and 4 cases in females aged years-old. The risk in older age groups is substantially lower. It is important to recognize that the risk of myocarditis associated with COVID is substantially higher. Patients present with new chest pain, shortness of breath, or palpitations after receiving an mRNA vaccine more common after the second dose.
But outcomes are good if associated with the vaccine. Most respond well to treatment and resolve symptoms within a week. There have been no deaths associated with vaccine-associated myocarditis. The risk of myocarditis is likely related to vaccine dose, so the fact that one-third the dose of the vaccine will be used in the year-olds is expected to correspond to a lower risk of myocarditis. At the lower dose given to younger kids, there has been a lower incidence of adverse effects reported compared to older children and adults who received the full dose.
In addition, baseline rates of myocarditis not associated with vaccination are much lower in children ages years than in older children, so the same may hold true for vaccine-associated myocarditis cases.
This is because myocarditis is associated with sex hormones particularly testosterone that surge during puberty. In support of this, the incidence of vaccine-associated myocarditis is lower in 12—year-old boys , compared to those who were older than 16 years old.
There were no cases of myocarditis reported in the experience to date of 5—year-old children in the trials, although the trial was too small to pick up on such a rare effect. There is a biologic basis for increasing the interval between vaccine doses in general. Priming the immune system with the first shot and then waiting gives the second shot a better chance of prompting a secondary immune reaction that results in a more durable response with more T cell driven immune memory.
One study from the U. In a study of British health care workers, there were twice as many neutralizing antibodies produced in a longer interval group weeks versus a shorter interval group weeks between doses. However, the safety and efficacy with longer intervals has not been evaluated in the pediatric or other COVID vaccine trials. In the U. Also, Europe is already experiencing a winter surge of infections that may predict more U.
During a time of high community virus burden with a highly transmissible Delta variant, relying on one dose of vaccine for several more weeks until the second may leave many more susceptible to infection while waiting.
There has been no corollary information in children but we would expect less protection in general from one vaccine dose vs. The current version, the DSM-5 , was released in , and collapsed autism, Asperger syndrome and pervasive developmental disorder-not otherwise specified into a single diagnosis.
Future estimates will be based on DSM-5 criteria—which may lower autism rates. Has the rising awareness of autism contributed to the prevalence? Increased awareness of autism has undoubtedly contributed to its rise in prevalence, Durkin says. Until the s, many people with autism were institutionalized, rendering them effectively invisible. Living close to urban centers and having access to good medical care also boost the likelihood of diagnosis. Greater awareness of autism is also likely to boost CDC estimates by increasing the chances that autism traits, such as lack of eye contact, show up in school and medical records, says Fombonne.
Policy changes may have also played a role. In , the American Academy of Pediatrics recommended screening all children for autism during routine pediatrician visits at 18 and 24 months of age. This move may have led to diagnoses for children who would otherwise have slipped under the radar. Are there other factors that ha ve influence d prevalence? Many individuals diagnosed with autism may, in the past, have been misdiagnosed with other conditions, such as intellectual disability: As diagnoses of autism have risen, those of intellectual disability have decreased.
This benefit makes clinicians more likely to diagnose a child with autism, even those who are on the borderline of the clinical criteria. Prior versions of the DSM did not allow for children to be diagnosed with both autism and attention deficit hyperactivity disorder. The DSM-5 allows multiple diagnoses, and most children with developmental delay are routinely screened for autism.
Autism prevalence has traditionally been highest in white children in the U. S, but this is starting to change. African-American and Hispanic children have lower rates of diagnosis because of a lack of access to services. Widespread screening has improved detection of autism in these groups, and raised overall prevalence.
Is there no real increase in autism rates, then? Awareness and changing criteria probably account for the bulk of the rise in prevalence, but biological factors might also contribute, says Durkin. For example, having older parents, particularly an older father , may boost the risk of autism. Children born prematurely also are at increased risk of autism, and more premature infants survive now than ever before.
This article is reproduced with permission from Spectrum. The article was first published on March 2, Already a subscriber?
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