Adenovirus is Common -- Why Not Another Vaccine? (MEDIUM ARTICLE_GAMBOA)

During my freshman fall quarter, I got really sick during finals week. In less than 24 hours, I was feverish, vomiting, coughing, and laying in bed with a sore throat and achy muscles. For the next week, I would lay in bed––except for the occasional trip to Vaden where I had x rays, blood work and IV treatments to restore my fluids. It took two weeks of resting, drinking lots of fluids and binge watching Netflix before I finally felt better.

Why did I get so sick? I had adenovirus. Adenovirus is a flu-like disease that causes a range of symptoms, including conjunctivitis, fever, pneumonia, bronchitis and diarrhea. It is commonly spread respiratorily, through close contact with another sick person or by touching surfaces with adenovirus on them. In fact, a girl who lived on the floor above me had very similar symptoms.

Adenovirus is a very common infection. It’s estimated to be responsible for between 2% and 5% of all respiratory infections. In winter, infection with type 4 or 7 causes recognisable illness in military recruits, with about 25% requiring hospitalisation for fever and lower respiratory tract disease. Adenovirus occur sporadically across the country and throughout the year. The scariest part of these outbreaks is how quickly the virus can spread––and how much damage it can leave in its wake. In 2018, adenovirus type 3 killed one 18-year-old college student, named Olivia Paregol, at the University of Maryland. Last year, a different adenovirus outbreak killed 11 children and made 36 sick in a nursing home in New Jersey. With more cases appearing, researchers and scientists have suggested changing current health policy––especially in regards to the adenovirus vaccine.

Yes, there is currently a licensed vaccine for adenovirus types 4 and 7 for military personnel only. The vaccines are available as two tablets; and a single tablet provides 99 percent protection from each of the viruses. The vaccine is recommended for military personnel because disease transmission rates can be especially high in their cramped living quarters. However, adenovirus is also commonly found in college dorms and schools, and even though the efficacy of the vaccine is excellent, there is no vaccine for the general public. This means that students like me are vulnerable to the disease while at school––and could end up missing their fall quarter finals because of it.

So why isn’t the vaccine available to the general public? The first reason is that the vaccine has not been tested in the general population or on people with weakened immune systems. There is reason to believe that it may lead to troubling consequences if we used it on a large scale. Secondly, and more importantly, there is little demand. Although adenovirus has caused some fatalities, it does not kill on the scale of the flu or HIV, for example. As mentioned earlier, adenovirus only causes 2% to 5% of all respiratory illnesses, suggesting that outbreaks are rare, contained and unburdensome. In other words, it would be very difficult to get people to vaccinate themselves against something that they don’t perceive as a threat.

However, the true threat of adenovirus may be currently underestimated. In a recent study at a college in Pennsylvania, 15 percent of students who showed up at clinics with influenza-like illnesses had adenovirus––mostly strains 3, 4 and 7. Another study completed by Magdalena Kendall Scott of the Oregon Public Health Division reported 198 adenovirus cases in two large Oregon hospital systems. “Adenovirus-7 might be reemerging in the United States and might be associated with increased numbers of severe respiratory infections,” Scott and researchers wrote in their 2016 report. 

Another problem that may prevent the production of a vaccine for the general public is the variety of adenovirus subtypes. According to the CDC, there are more than 51 strains of adenovirus. With so much genetic variety, researchers and biologists would have to decide which strain to target; or they would have to discover how to create a vaccine with universal potential––which has yet to be done. Though the current vaccine is remarkably effective, the vaccine has its limitations. The adenovirus vaccine is made out of live-attenuated virus, which is a fancy way of saying the virus has been crippled or weakened. After vaccination, the live viral particles may be released from the pill into the gut. Because it is live, the virus may be shed in stool and might spread. This would be particularly harmful, as it would leave the elderly, children and the immunocompromised especially vulnerable. 

All in all, there is little reason to believe a public adenovirus vaccine will be available any time soon. Without market demand or financial incentives, pharmaceutical companies have diverted their interests and are instead prioritizing other research. This means hundreds of people will remain at risk, as the number of cases in the U.S. continues to climb. Today, ongoing surveillance by the CDC focuses on which adenovirus strains are circulating in the population. With this data, we may be taking baby steps towards protection. 

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Sources: https://www.cdc.gov/adenovirus/index.html , https://www.cdc.gov/vaccines/hcp/vis/vis-statements/adenovirus.html, https://www.cdc.gov/adenovirus/outbreaks.html, https://www.nbcnews.com/health/health-news/adenovirus-killed-college-student-there-s-vaccine-she-couldn-t-n951061, https://www.who.int/water_sanitation_health/bathing/recreadischap6.pdf