Clinical and epidemiological impact of varicella infection in children prior to the introduction of the varicella vaccine in the national immunization schedule of Argentina

Abstract

Introduction. In Argentina, an estimated 400 000 varicella cases occur annually. Given the under-recording of existing cases, the actual burden of disease is unknown. Objective. To assess the burden of varicella before the introduction of the varicella vaccine in the national immunization schedule. Materials and methods. Retrospective, analytical, observational study carried out in three hospitals of Argentina. Review of medical records from outpatient visits to the Emergency Department and from patients younger than 18 years hospitalized for varicella. Period: 1/2011-12/2013. Results. A total of 382 782 outpatients were seen; 3367 (0.88 %) corresponded to visits due to varicella; 57.6 % were ≤ 4 years old. A total of 164 (4.9 %) patients required hospitalization, with an overall hospitalization rate of 65.3/10 000 hospitalized patients/year (95 % confidence interval [CI]: 55.4-76.5); hospitalization rate in healthy children: 57.2/10 000 (95 % CI: 67.7-48.0); median age: 31.5 months. The most common causes of hospitalization were skin and/or soft tissue infections (61.1 %) and respiratory infections (10.1 %). Also, 54.3 % were treated with acyclovir and 73.1 %, with antibiotics. Bacteremia developed in 5/67 patients (7.5 %), all cases were caused by Gram-positive cocci and occurred in immunocompetent patients. Out of 19 immunocompromised patients, 36.8 % had complications (5 skin and/or soft tissue infection and 2 pneumonia cases). The median length of stay was 4 days, which is significantly more prolonged in immunocompromised patients. One patient required intensive care. No patient died. Conclusion. The burden of disease was significant, with a considerable impact in patients without an underlying disease.

Global Prevalence of Varicella-Associated Complications: A Systematic Review and Meta-Analysis

“…Of these, 52 studies were excluded from the meta-analysis, leaving 78 studies eligible for meta-analysis (Fig. 1 ) [ 6 – 9 , 28 , 30 – 32 , 34 , 35 , 37 , 38 , 41 , 43 , 46 , 47 , 51 , 53 , 57 – 68 , 71 – 74 , 76 – 78 , 81 , 85 , 87 , 91 – 94 , 99 – 102 , 104 , 105 , 107 , 109 , 112 – 114 , 116 – 118 , 120 , 121 , 124 , 125 , 128 – 132 , 134 , 136 , 138 – 140 , 142 , 143 , 145 – 147 , 150 ]. From the selected studies, 632 unique complications were extracted, of which 303 were included after clinical review.…”

“…Previous literature has indicated that varicella complications occur mostly among immunocompromised patients [ 113 ], although recent studies have demonstrated that the burden of varicella complications is significant in patients without underlying disease [ 112 , 157 ]. The present study observed that immunocompetent patients when compared with immunocompromised patients had a significantly higher prevalence of neurological (11.73% vs 2.65%) and skin (27.49% vs 7.17%) complications.…”

Trends in Varicella Burden of Disease Following Introduction of Routine Childhood Varicella Vaccination in Argentina: A 12-Year Time Series Analysis

“…However, varicella-associated complications can occur in up to 12% of outpatients and 92.6% of inpatients [ 3 , 4 , 5 , 6 , 7 , 8 ]. Approximately 5% of patients with varicella who seek medical services will require hospitalization [ 9 ]. The most common complications are secondary bacterial infections of the skin and soft tissues, followed by pneumonia and encephalitis [ 3 , 4 , 5 , 6 , 7 , 8 ].…”

“…In countries with temperate climates such as Argentina, varicella is primarily a seasonal childhood disease with most cases occurring in late winter and spring (September to November) [ 9 , 10 , 11 ]. In regions with tropical and subtropical climates, varicella tends to be more pronounced in adolescents and adults [ 1 ].…”

Epidemiological Impact of Universal Varicella Vaccination on Consecutive Emergency Department Visits for Varicella and Its Cost-Effectiveness Among Children

“…VZV infection is generally a mild illness consisting of moderate fever, mild cold symptoms, and a vesicular rash that develops scabs [1]. Some cases of varicella lead to serious complications such as encephalitis, pneumonia, and secondary bacterial infections; rarely, it results in death, especially for children younger than 1 year, immunocompromised patients, patients with impaired malignancies, and patients using immunosuppressive medications [1][2][3][4].…”