Epidemiological and clinical characteristics and the approach to infant chickenpox in primary care.

Chickenpox is not common in the first year of life (infant varicella) and there is a lack of data on its presentation, especially in primary care. A year-long observational study (July 2015-2016) carried out by a research network of primary care pediatricians throughout Spain.Two hundred and sixty-four pediatricians gathered data from 358 cases of clinically diagnosed chickenpox in infants. The illness was considered mild in 78% of infants < 7 months compared to 65% in those aged 7 to 12 months (p = 0.0144). Fever (46%) was present in 35% of children ≤ 6 months compared to 55% in older children (p = 0.0005). The number of skin lesions was > 50 in 35% of children ≤ 6 months old compared to 47% in > 7 months (p = 0.0273). From the 2% of hospitalized children 86% were younger than 7 months. Oral antiviral treatment was given in 33% of cases ≤ 6 months compared to 18% in older patients (p = 0.0023). Doubts about administering the chickenpox vaccine at a later date were expressed by 18% of pediatricians.Conclusion: Chickenpox is considered benign, having a mild effect on most infants. There is less clinical effect in infants ≤ 6 months although this age group is hospitalized more and is prescribed more antiviral treatment. There are doubts among pediatricians about the subsequent need for vaccination. What is Known: • Chickenpox is uncommon and of uncertain evolution in the first year of life • Hospital admissions for chickenpox are more frequent in the first year of life What is New: • The course of chickenpox in the first year of life is mild, especially in infants younger than 7 months despite the fact they are hospitalized more and are treated more frequently with antivirals. Antivirals are prescribed to 1 in 4 children with chickenpox under 12 months of age. • Almost 50% of pediatricians recommend a subsequent vaccination against chickenpox especially if it occurs in the first 6 months of life.