Cytomegalovirus vaccine
A Cytomegalovirus (CMV) vaccine aims to protect individuals, particularly pregnant women, from CMV infection, which is the most common congenital infection in the United States. CMV can cause severe health issues in affected newborns, including hearing and vision loss, developmental delays, and other serious conditions. The virus is often transmitted through contact with young children, making those who have close interactions, such as parents and caregivers, particularly vulnerable. Current preventive measures, including hygiene practices and antiviral medications, have been largely ineffective, highlighting the critical need for a vaccine. Several vaccine candidates, including the Towne and MF59 vaccines, are undergoing clinical trials, showing promising results in establishing immunity and reducing disease transmission. However, challenges remain in recruitment for trials and the need for long-term studies to assess effectiveness. With around 8,000 newborns affected annually, an effective CMV vaccine could significantly reduce both health complications and the economic burden on healthcare systems. Despite ongoing research efforts, no CMV vaccine has yet been approved for public use.
Cytomegalovirus vaccine
Definition
No vaccine exists for cytomegalovirus (CMV) infection, the most common congenital infection in the United States. Severely affected newborns may have hearing loss, vision loss, mental retardation, cerebral palsy, seizures, and liver disease. CMV is also frequently acquired in immunocompromised persons, such as those with human immunodeficiency virus (HIV) infection or cancer and those who have had organ transplants. Persons with compromised immune systems are consequently at risk for developing additional life-threatening infections.
CMV is primarily spread by contact with young children who excrete the virus. Earlier attempts to prevent CMV transmission by increased hygienic practices, such as handwashing and avoiding handling of children, proved unsuccessful, and antiviral medications have low efficacy.
Potential CMV Vaccines
Pregnant women without a history of CMV infection and who have close contact with young children are at greatest risk of contracting the virus and transmitting it to a fetus. Therefore, the primary goal of the CMV vaccine would be to give at-risk women immunity to the virus before giving birth. There have been potential vaccine candidates, although they did not make it to phase 3 trials. An experimental mRNA vaccination elicited promising immune responses, according to a study by researchers at Weill Cornell Medicine. The vaccine, which is manufactured by Moderna, Inc., may protect adults against CMV, which could prevent pregnant women from passing the infection on to their child.
Development Challenges
All vaccines have been shown to be safe, but studies are limited by difficulty in recruiting study subjects because of a lack of public awareness of CMV, by the need for a large sample size, and by the need for long-term follow-up. Additionally, many women enrolled in vaccine trials have increased their handwashing frequency and have decreased exposure to young children, making it difficult to determine if the vaccine, or the change in behavior, is determining the outcome. Also, debate remains about what population should be targeted for vaccine administration.
Impact
Approximately one in four newborns born each year have severe medical and neurological concerns related to congenital CMV infection, translating into a yearly national healthcare cost of $1.86 billion. An effective CMV vaccine not only would decrease the rate of infection but also would reduce the economic burden for treating the related diseases. Despite ongoing research efforts from the Centers for Disease Control and Prevention, the US Food and Drug Administration, and National Institutes of Health, no approved CMV vaccine is available.
Bibliography
Adler, Stuart, et al. “Recent Advances in the Prevention and Treatment of Congenital Cytomegalovirus Infections.” Seminars in Perinatology 31 (2007): 10-18.
Arvin, Ann, et al. “Vaccine Development to Prevent Cytomegalovirus Disease: Report from the National Vaccine Advisory Committee.” Vaccines 39 (2004): 233-239.
Dekker, Cornelia, and Ann Arvin. “One Step Closer to a CMV Vaccine.” New England Journal of Medicine 360 (2009): 1250-1252.
Diaz-Decaro, John D. et al. "Economic Burden of Congenital Cytomegalovirus Infection in Commerciallyand Medicaid-insured Patients in the United States." Open Forum Infectious Diseases, vol. 9, no. 2, 15 Dec. 2022, doi.org/10.1093/ofid/ofac492.1765. Accessed 2 Feb. 2025.
Martin, Richard J., Avroy A. Fanaroff, and Michele C. Walsh, eds. Fanaroff and Martin’s Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. 2 vols. 8th ed. Philadelphia: Mosby/Elsevier, 2006.
Salome, S. et al. "Congenital Cytomegalovirus Infection: The State of the Art and Future Perspectives." Frontiers in Pediatrics, vol. 11, 16 Nov. 2023, doi: 10.3389/fped.2023.1276912. Accessed 2 Feb. 2025.
"Vaccine Shows Promise Against CMV, a Virus That Causes Birth Defects." Weill Cornell Medicine, 7 Feb. 2024, news.weill.cornell.edu/news/2024/02/vaccine-shows-promise-against-cmv-a-virus-that-causes-birth-defects. Accessed 2 Feb. 2025.