Seroprevalence of influenza A and B viruses among unvaccinated children in the United Arab Emirates: a cross-sectional study.

BACKGROUND: Young children are at increased risk of severe influenza disease and, thus, are good candidates for receiving annual vaccination. Nevertheless, the influenza vaccine is infrequently given to children in our region. The primary objectives of this study are to monitor the serologic immunities against influenza A and B viruses, and provide pediatric data that support the need for influenza vaccination in the community. METHODS: Influenza A and B virus-specific IgG antibodies were measured in 294 children (median age 4.1 years; range 1.9-12.5 years) between July 2014 and September 2015. RESULTS: The percentage of children who were seropositive for influenza A IgG was 15.8%, equivocal 7.4%, and negative 76.8%. The corresponding values for influenza B IgG were 31.3, 9.6, and 59.1%, respectively. There was a higher seropositivity rate for influenza B than for influenza A in all age groups. The percentage of children who were seropositive for either influenza A or B IgG was 27.9% and for both was only 2.7%. CONCLUSIONS: Most of the studied children are serologically naïve and, thus, are likely to acquire primary influenza disease. A national policy that endorses childhood influenza vaccination is highly advisable.

Seroprevalence of vaccine-preventable diseases among young children in the United Arab Emirates.

OBJECTIVES: In the United Arab Emirates (UAE), many vaccine-preventable diseases are notifiable and are often reported despite high estimated immunization coverage. The serological assessment of immunity against these infections (serosurveillance) complements disease surveillance (notification). This study aimed to assess the yet unmeasured serological immunities to nine vaccine-preventable infections among vaccinated Emirati children. METHODS: This cross-sectional study involved children who attended the Well-Child Care Programme of the Ambulatory Healthcare Services (Al-Ain, UAE) between July 2014 and September 2015. Serological testing was performed in 227 Emirati children (49% females); subjects were aged (mean±standard deviation) 45±14 months (median 43, range 23-71 months). RESULTS: The seroprevalence rates varied markedly among the studied vaccine-preventable diseases, ranging from 39.2% (pertussis) to 98.3% (rubella). Other high seroprevalence rates were noted for measles (98.2%) and poliovirus (92%). The seroprevalence rate for mumps was 82.8%, for varicella was 68.3%, for diphtheria was 86.4%, for tetanus was 89.9%, and for Haemophilus influenzae type B was 84.1%. CONCLUSIONS: A large number of the studied children had low seroprevalence rates against pertussis, varicella, and mumps. Studies are needed to explore whether modifying the national immunization programme could improve these low seroprevalence estimates.

Prevalence of neutropenia in children by nationality.

BACKGROUND: A high prevalence of neutropenia has been reported in several ethnic groups amongst whom many healthy individuals with low neutrophil counts undergo unnecessary investigations. This study aims to ascertain the prevalence of neutropenia (NP) in a large cohort of children from North African, Middle Eastern, and Asian countries residing in the United Arab Emirates. METHODS: Neutrophil counts of 26,542 children (one day to six years of age) from 86 countries were analyzed. The subjects were enrolled in the Well-Child-Care program of Ambulatory Health Services of Emirate of Abu Dhabi, United Arab Emirates. NP was defined as a neutrophil count <1.5 × 10(9)/L and severe NP <0.5 × 10(9)/L. RESULTS: The neutrophil counts reached a nadir in the fourth week of life and changed slightly from the age of six-months to six-years. The frequency of NP was (from West-to-East): North African Arabs 15.4 %, Green Crescent Arabs 9.8 %, Peninsular Arabs 10.9 %, Iranians 3.1 %, Afghanis 2.5 %, Pakistanis 5.6 %, Indians 10.2 %, and Filipinos 7.3 %. The frequency of severe NP in North African Arabs (Sudanese) was 2.8 %, Green Crescent and Peninsular Arabs ≤1 %, Indians 1.5 %, and Filipinos 1.8 %. In 12,703 Emirati children, the frequency of NP was 10.6 % similar to their adult counterparts. CONCLUSION: The prevalence of childhood NP varied considerably by geoethnicity. Measures to prevent the inappropriate investigations of healthy children with benign neutropenia are proposed.

The use of an interferon-gamma release assay to screen for pediatric latent tuberculosis infection in the eastern region of the Emirate of Abu Dhabi.

OBJECTIVES: Intense migration to the United Arab Emirates from tuberculosis (TB) high-endemic areas presents a particular risk to the population. Screening for latent tuberculosis infection (LTBI) usually involves risk assessment, the tuberculin skin test (TST), and interferon-gamma release assay (IGRA). This study investigated the use of an IGRA to screen for LTBI and compared its performance with a risk assessment questionnaire. METHODS: This prospective cross-sectional study was conducted at seven Ambulatory Healthcare Services facilities in Abu Dhabi. Participants (88% Emiratis) were pediatric patients presenting for routine care. The QuantiFERON-TB Gold In-Tube test was performed and the parents completed a questionnaire assessing TB risk factors. RESULTS: Six-hundred and ninety-nine subjects (median age 8.7 years, interquartile range 9.2 years) were enrolled; 669 (96%) agreed to testing. Four patients had a positive IGRA; one had previously been treated for TB, resulting in three patients with LTBI. The estimated LTBI prevalence was 0.45% (95% confidence interval 0.09-1.3). A household contact from a TB high-endemic area was reported in 44%, travel to a TB high-endemic area in 10%, and contact with someone with a chronic cough in 7%, a TB case in 3%, a TST-positive case in 2%, and an IGRA-positive case in 2%. Fifty percent of participants had at least one risk factor. The risk assessment did not predict a positive IGRA. CONCLUSIONS: The questionnaire yielded a risk of TB exposure of 50%, however the LTBI prevalence, as defined by the IGRA, was low (0.45%).