Symptomatic and asymptomatic re-infection with rotaviruses occurs frequently. However, the severity and the number of rotavirus infections usually decrease with subsequent infection.7
In a study by Velázquez and colleagues in Mexico, a cohort of 200 infants was followed from birth to 2 years of age and monitored weekly for rotavirus infection.7
The study showed that natural rotavirus infection afforded protection against the entire range of outcomes, ranging from asymptomatic infection to moderate-to-severe diarrhea.7
The study also found that primary infection induced a partially protective immune response but multiple infections were needed to achieve greater protection.7 The degree of protection increased with the number of infections and was greatest against moderate-to-severe illness after the second infection.7
Protection Conferred by Natural Rotavirus Infection
| Adjusted Efficacy After Each Infection, % (95% CI)* |
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* Efficacy was calculated as the percent reduction in the risk of an outcome as compared with the risk for children who were not yet infected. CI=Credibility Interval |
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| Selected outcomes of rotavirus infection |
After first infection | After second infection | After third infection |
| Moderate-to-severe diarrhea | 87% (55 to 96%) |
100% | ------ |
| Mild diarrhea | 73% (50 to 86%) |
75% (45 to 89%) |
99% (-100 to 100%) |
| Asymptomatic infection | 38% (9 to 58%) |
62% (34 to 79%) |
74% (17 to 92%) |
Adapted from Velázquez FR et al7
The development of virus-specific secretory immunoglobulin A (sIgA) at the intestinal mucosal surface has been shown to be of primary importance in protection against rotavirus disease.21
Homotypic Versus Heterotypic Immunity:
In general, multiple infections are needed to achieve complete protection because rotaviruses are present in multiple serotypes.7
Evidence indicates that immunity resulting from initial exposure to natural rotavirus infection is serotype-specific; thus, infection with one serotype can leave people at risk for infections from other serotypes.8
In the Velázquez study of children infected twice with rotavirus:7,*
Adapted from Velázquez FR et al7
The G type was determined for 76% of the 177 strains of rotavirus identified in fecal specimens. The G types were determined in 22 pairs of strains isolated from first and second infections.
Ninety-one percent of children were infected the second time with a different serotype.7
* A cohort of 200 Mexican infants was followed from birth to 2 years of age and monitored weekly for rotavirus infection.