Vaccines are always in the news it seems, but there was a bit of a spike in activity over the past several weeks. Unfortunately, not all of it is good news. In this brief post, I’ll run through a few of the more interesting updates.
Fewer rotavirus infections, less type 1 diabetes in kids
Back in February, I wrote a post about a study showing that the infant rotavirus vaccine might protect young children against more than just a bad case of diarrhea:
Late last month, a study out of Australia published in JAMA Pediatrics found a 14% reduction in the diagnosis of type 1 diabetes in rotavirus vaccinated children through age 4 years. They compared the rate of this diagnosis during the 8 years before and after introduction of the vaccine in May of 2007. Unfortunately, they did not see a decrease in older children.
I pointed out at the time that the data was preliminary but exciting. Well, I’ve got some good news. A cohort study published in June and involving nearly 1.5 million American infants has replicated these results. In fact, the new study found an even more impressive apparent reduction in the risk of type 1 diabetes, clocking in at more than 30%, when children are fully protected against rotavirus infection:
We found a significant reduction in the incidence of type 1 diabetes in children who received the entire rotavirus vaccination series compared to both a contemporary cohort and a historical cohort who were not vaccinated. There was no reduction in incidence in children who received only part of the recommended vaccination series. The pentavalent vaccine, in particular, was associated with lower risk. These results support the findings from Australia and the decrease in type 1 diabetes incidence in children <5 years observed in the SEARCH for diabetes in youth registry. The rotavirus vaccine appeared safe with fewer hospitalizations among those vaccinated.
Obviously we can’t say with certainty that there is a proven causal relationship between the vaccine a lower risk of diabetes. After all, it would be unethical at this point to do a prospective controlled study because of the proven benefit from reducing the incidence of rotavirus infection. But taking into account two large studies in two different countries, plus the established plausibility that rotavirus infection might result in an autoimmune process that leads to type 1 diabetes, I’m comfortable adding this to the list of vaccine benefits.
Childhood chickenpox vaccine reduces the risk of childhood shingles
Chickenpox and shingles are two conditions caused by the same pathogen: the varicella-zoster virus or VZV. After an initial infection with VZV in childhood, such as when I came down with those infamous itchy blisters back in the 2nd grade, the virus isn’t eradicated. We don’t have a full understanding of the pathophysiology, but after a case of chickenpox the virus appears to remain dormant in certain nerves near the brain and spinal cord only to reappear as painful shingles lesions. This most commonly occurs after age 50 but can happen at any point.
A vaccine against VZV rolled out in 1996, and subsequently the incidence of chickenpox has plummeted. I haven’t personally seen a case in years. And when they do occur in a vaccinated child, they tend to be fairly mild with only a few lesions instead of potentially hundreds.
Naturally one of the biggest questions regarding the vaccine, which is made using live but weakened virus, has been the potential effect on the incidence of shingles. Smaller studies have had somewhat murky results, but a study involving over 6 millions patients was published in July that helped clear things up. It showed that routine VZV immunization lowered the rate of shingles in children under 18 years from 170 to 38 per 100,000, with the exception that vaccinated children in the 2nd year of life were found to be at higher risk of developing shingles.
Because widespread availability of the vaccine was only a little over twenty years ago, we don’t know what will happen with the incidence of shingles in older adult populations. Most experts believe that it will decrease, likely dramatically. But long term studies need to be done to know for sure. In the meantime, there is an effective vaccine against shingles that is recommended for adults over the age of 60.
Influenza vaccine is still safe during pregnancy
A recent Canadian study of over 100,000 children adds to the data showing that it is safe for pregnant women to receive the flu shot. The study looked at rates of “immune related (infectious diseases, asthma), non-immune related (neoplasms, sensory disorders), and non-specific morbidity outcomes (urgent or inpatient health services use, pediatric complex chronic conditions)” from birth to 5 years of age:
Overall, our findings indicate that 2009 pH1N1 influenza vaccination in pregnancy was not associated with negative five year health outcomes in children, which is reassuring and consistent with a similar recent study from Denmark.
Speaking of the flu shot. It’s time for you to get yours. Now.
Many adults aren’t aware of the HPV vaccine
This July survey was small, with only about 1,500 respondents aged 18 to 59 years, but still frustrating. Only 290 of the 1,500 adults were familiar with HPV vaccine. But it gets worse. Of the 290 people who were at least aware that the HPV vaccine is a thing, only about 60% supported a policy to require pediatricians to offer it. And only 40% supported making the vaccine a requirement for attending public schools. Adding insult to injury, only 44% and 15% of the female and male respondents respectively were immunized against this cancer causing virus.
Measles elimination status at risk
In 2000, the United States was declared free of endemic measles infections. Things have changed as of late. When I wrote about the 2019 measles outbreaks in May, we had already broken a record more than 2 decades old. We topped 1,000 cases within a couple weeks of that post and are currently at 1,243 with 12 new cases last week. It does appear to be slowing down at least.
According to an August announcement by the WHO, four countries have lost their measles elimination status because of recent outbreaks. These include Albania, the Czech Republic, Greece, and most recently the United Kingdom. Up next appears to be the United States. In order to achieve this dubious distinction, there only needs to be one additional case in October that is linked to the ongoing outbreaks in New York City and Rockland County. Just one case.
Now back to the unraveling of the American government.