Estimating the burden of influenza‐associated hospitalization and deaths in Oman (2012‐2015)

Abstract

BackgroundInfluenza is a serious vaccine‐preventable disease with high incidence, hospitalization, and mortality in high‐risk groups. The epidemiology, seasonality, and risk factors for influenza are well defined in most of the temperate countries, but estimating influenza burden in the World Health Organization (WHO) Region for the Eastern Mediterranean is scarce. In Oman, despite the advancements in influenza surveillance, the clinical burden and seasonality of influenza remain not fully understood.ObjectivesTo estimate the incidence of influenza‐associated hospitalizations and in‐hospital death in Oman.Patients and methodsInfluenza‐associated hospitalizations and in‐hospital deaths were estimated using hospital discharge records based on ICD‐10 codes (J09‐J18), results of virological analysis and population census for the period between 2012 and 2015.ResultsDuring 2012 and 2015, we identified a total of 19 405 influenza‐associated hospitalization and 847 deaths. Influenza positivity percentage ranged from 6.4% in 2013 to 20.6% in 2015. Influenza‐associated hospitalization incidence rate was 7.3 (95% CI: 6.4‐8.1) per 100 000 in 2013 and 27.5 (95% CI: 25.9‐29.1) per 100 000 in 2015 with an overall rate of 20.6 (95% CI: 19.9‐21.3) per 100 000. The highest incidence of influenza‐associated death was among those aged ≥65 years and ranged between 39.5 (95% CI: 27.3‐51.8) per 100 000 in 2014 and 11.3 (95% CI: 7.5‐15.1) in 2015.ConclusionsInfluenza causes a substantial number of hospitalizations and deaths in Oman. Hospitalization rates were highest among children, and adults ≥65 years showed the highest death rate. The potential value of using seasonal influenza vaccine in these groups should be considered.

Estimates of influenza‐associated hospitalisations in tropical Singapore, 2010‐2017: Higher burden estimated in more recent years

“…Our estimate was however lower than that of Chile (excess SARI hospitalisation rate of 71.5 per 100 000 person‐years for 2012‐2014), Hong Kong (excess P&I hospitalisation rate of 74.3 per 100 000 person‐years for 1998‐2013) and the United States (average yearly hospitalisations of 133 per 100 000 persons for 2010/2011‐2016/2017) . As discussed by Abdel‐Hady et al, it is difficult to make like‐for‐like comparisons between the countries' estimates due to different outcome variables used (ie P&I vs SARI vs all‐cause hospitalisations), unequal health‐seeking behaviour (accessibility to healthcare at an acute hospital), non‐identical methodologies (multiplication method vs statistical regression models) and different study periods. It is notable that given the year‐round influenza activity in Singapore, our annual influenza positivity percentages were consistently more than 40% every year; this is more than double that reported by Chile and Oman (averages of 8.8% and 17%, respectively), countries that experience distinct influenza seasons in the winter .…”

“…Our overall estimated excess P&I hospitalisation rate of 50.1 per 100 000 person‐years was higher than the average seasonal excess P&I hospitalisation rate of 19.4 per 100 000 persons reported by Portugal from 1998/1999 to 2014/2015, and the overall excess severe acute respiratory infection (SARI) hospitalisation rate of 20.6 per 100 000 persons reported by Oman for 2012‐2015 . It was also higher than the annual excess SARI hospitalisation rate of 13‐19 per 100 000 persons from 2013/14 to 2015/16 reported by Indonesia, which has a similar tropical climate.…”

“…As discussed by Abdel‐Hady et al, it is difficult to make like‐for‐like comparisons between the countries' estimates due to different outcome variables used (ie P&I vs SARI vs all‐cause hospitalisations), unequal health‐seeking behaviour (accessibility to healthcare at an acute hospital), non‐identical methodologies (multiplication method vs statistical regression models) and different study periods. It is notable that given the year‐round influenza activity in Singapore, our annual influenza positivity percentages were consistently more than 40% every year; this is more than double that reported by Chile and Oman (averages of 8.8% and 17%, respectively), countries that experience distinct influenza seasons in the winter . Hence, it could be possible that the burden imposed by influenza on countries with year‐round influenza activity is relatively greater in a calendar year, with all other things being equal.…”

Pandemic influenza preparedness (PIP) framework: Progress challenges in improving influenza preparedness response capacities in the Eastern Mediterranean Region, 2014–2017

“…By the end of 2017, nearly one-third of countries (seven out of 22) in the Region had estimated their disease burden including three L&S PIP priority countries. Five countries have already published their findings (Egypt, Iran (Islamic Republic of), Lebanon, Oman and Tunis) [16][17][18][19][20], while the manuscripts from Jordan and Morocco are under peer-review. National disease burden estimates can now be used by countries to inform pandemic influenza policy such as for risk-group identification and response measures required.…”

Fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance (EMARIS) network and first scientific conference on acute respiratory infections in the Eastern Mediterranean Region, 11-14 December, 2017, Amman, Jordan

“…Data are regularly shared with FluID and EMFLU (Eastern Mediterranean Flu Network)-the online portal for sharing influenza surveillance data. Egypt, Iran, Jordan, Lebanon, Oman and Tunisia have now estimated their influenza disease burden using surveillance data [11]. The seasonality and epidemiology of influenza are now better understood in different influenza transmission zones of the Region.…”