A new systematic analysis of tens of thousands of studies confirms, yet again, that childhood vaccinations are overwhelmingly safe for use.
Back in 2011, an analysis of 1,000 peer reviewed studies showed that, as existing literature had already found, childhood vaccinations are safe and the likelihood of complications are extremely low. The study, authored by multiple medical groups under the Institute of Medicine (IOM) umbrella, found no link between the MMR vaccine and autism, and the data showed that the vast majority of vaccines carry little no risk to a child’s health.
Of the few that were shown to raise the chances of developing some sort of health complications, like particular vaccines, those instances were few and far between and the chances of serious health problems, like anaphylaxis, even more rare. In essence, vaccines were found to be a safe and cost effective way of preventing numerous diseases.
That study remains the most comprehensive of its kind, and researchers wanted to build off that work to continue to assess vaccine safety. Now, three years on, researchers have attempted to update that information with a new systematic review, which involves gathering together large amounts of data on the topic, selecting studies from it based on quality and other criteria, and then synthesizing an impartial overview. This leaves little room for fudging or biasing the results.
Since 2011 around 3,000 studies have been conducted on vaccine safety. The latest review whittles those down to 67 scientific papers, with criteria for selection being robust control groups and follow-up reports after the main research has concluded. The research also draws on more than 20,000 science titles. If anything, this puts the threshold for vaccine safety very high.
Published this month in the journal Pediatrics, the latest systematic analysis also included new research that wasn’t present in the 2011 analysis on things like the hepatitis vaccines, and we’ll deal with that first. The new analysis showed that the hepatitis B vaccine does not appear to cause adverse effects, despite what some groups have claimed. The research also again found no link between the MMR vaccine and autism. Furthermore, the polio vaccine was not associated with creating food allergies, as has been claimed, and absolutely no vaccine was linked with causing leukemia or death.
The research did find that some vaccines carried a small risk of potential health problems. For instance, the meningitis and pneumonia vaccine known as the Hib or Hib/C vaccine had a small but significant link with developing a mild, localized rash around the injection site. The analysis showed that, without any other underlying condition, this did not progress into anything more serious.
More moderately serious reactions were observable for other vaccines. The hepatitis A vaccine, as well as the MMR and chicken pox vaccine, were shown to carry the risk of recipients developing what’s known as purpura, which is a skin rash caused by small blood vessels near the surface of the skin leaking. Again, on its own this is not a serious condition.
In terms of potentially serious health problems, the MMR vaccine and the TIV flu vaccine were in a minority of cases linked to fever related seizures, but again this was rare. Some vaccines were linked with the potential for anaphylaxis but this was usually attributable to existing allergies and not a spontaneous event. Lastly, there was some evidence that the two rotavirus vaccinations can twist the bowels of children, but that condition is treatable and has not directly led to any fatalities.
In conclusion, the authors of the study found that the complications relating to vaccines are very rare. Weighed against the massive benefits that vaccines have brought us, in some cases eliminating certain childhood diseases, the researchers believe these findings illustrate very clearly why anti-vaccine paranoia is unfounded.
“We found that serious adverse events that are linked to vaccines are really rare, and that when they do occur they are often not necessarily severe,” Courtney Gidengil, co-author of this systematic analysis, told the press. “We think this adds to the body of evidence that the benefits really do seem to clearly outweigh the low risk of serious side effects from vaccines.”
Given that the United States is currently experiencing an 18-year high of measles cases, and how anti-vaccination groups continue to make Americans feel uncertain about whether they should vaccinate their children based on flawed research, this research is vital for presenting the facts, which are that vaccines have repeatedly been shown to be effective, and indeed that they have saved countless lives.
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