Rotavirus is a highly contagious agent that causes severe diarrheal disease, primarily affecting infants and young children worldwide. Before the introduction of a vaccine, almost every child in the United States experienced a rotavirus infection by age five. Reinfection is possible, but the body’s immune response changes the experience significantly.
Understanding Rotavirus Infection
Rotavirus causes gastroenteritis, an inflammation of the stomach and intestines that results in severe watery diarrhea and vomiting, commonly lasting for three to eight days. Fever and abdominal pain are also frequent symptoms that may appear before the diarrhea begins. The severity of the symptoms often leads to significant fluid loss, making dehydration the main complication that may require hospitalization, especially in young children.
The virus is transmitted primarily through the fecal-oral route, meaning microscopic particles of stool from an infected person are ingested by another individual. Rotavirus is stable and can survive on surfaces like toys or doorknobs for days. This stability allows rotavirus to spread easily in environments like daycare centers and schools.
Reinfection and Acquired Immunity
A single natural infection does not provide complete, lasting immunity, making reinfection possible at any age. The virus has multiple strains, or serotypes, which complicates the immune response. These serotypes are defined by two proteins on the outer shell, VP7 and VP4, which are the targets for neutralizing antibodies.
The body develops protection partially specific to the infecting serotype. While an initial infection may not fully protect against a different serotype encountered later, the immune system gains partial protection against subsequent infections, even those caused by a different strain.
Subsequent infections are typically milder, shorter in duration, or may even be completely asymptomatic. Each additional exposure, whether symptomatic or not, progressively strengthens the immunity. This progressive protection means that while a person can be reinfected multiple times, the risk of developing a severe illness decreases significantly with each encounter.
Preventing Rotavirus Infection
The most effective strategy for preventing rotavirus disease is vaccination, a routine part of the childhood immunization schedule. The rotavirus vaccine is an oral preparation, administered as drops into the infant’s mouth rather than an injection. Depending on the brand, the vaccine is given in either a two-dose or three-dose series.
The first dose is recommended before the infant reaches 15 weeks of age, and all required doses must be completed before they turn eight months old. Completing the full series provides a high degree of protection, reducing the risk of severe rotavirus illness and hospitalization by 85% to 98%. The vaccine also offers indirect protection by lowering the overall spread of the virus in the community.
Sanitation measures serve as an important secondary layer of prevention against this highly transmissible virus. Thorough and frequent handwashing, especially after diaper changes or using the restroom, helps to interrupt the fecal-oral route of transmission. Disinfecting household surfaces can also reduce the chance of spread, as the virus can remain viable in the environment for an extended time.