@article{de Lange_Teirlinck_Dijkstra_Stoeldraijer_Harmsen_van der Hoek_2017, title={Mortality surveillance in the Netherlands: winter 2015/2016 of moderate severity}, volume={9}, url={https://ojphi.org/ojs/index.php/ojphi/article/view/7699}, DOI={10.5210/ojphi.v9i1.7699}, abstractNote={<div style="left: 78.2727px; top: 309.402px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.0823);" data-canvas-width="55.467823232323234">Objective</div><div style="left: 91.3182px; top: 322.405px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01861);" data-canvas-width="329.7070494949495">Weekly numbers of deaths are monitored to increase the capacity</div><div style="left: 78.2727px; top: 336.9px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.985207);" data-canvas-width="344.19866515151506">to deal with both expected and unusual (disease) events such as</div><div style="left: 78.2727px; top: 351.395px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.984046);" data-canvas-width="343.7107651515152">pandemic influenza, other infections and non-infectious incidents.</div><div style="left: 78.2727px; top: 365.89px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02959);" data-canvas-width="343.0577676767679">The monitoring information can potentially be used to detect, track</div><div style="left: 78.2727px; top: 380.384px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.995657);" data-canvas-width="344.4475434343438">and estimate the impact of an outbreak or incident on all-cause</div><div style="left: 78.2727px; top: 394.879px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01886);" data-canvas-width="48.260209595959594">mortality.</div><div style="left: 78.2727px; top: 422.462px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.11884);" data-canvas-width="71.86668434343434">Introduction</div><div style="left: 91.3182px; top: 435.465px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.989998);" data-canvas-width="330.95636919191907">The mortality monitoring system (initiated in 2009 during the</div><div style="left: 78.2727px; top: 449.96px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0093);" data-canvas-width="342.507032070707">influenza A(H1N1) pandemic) is a collaboration between the Centre</div><div style="left: 78.2727px; top: 464.455px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01302);" data-canvas-width="344.511611111111">for Infectious Disease Control (CIb) and Statistics Netherlands.</div><div style="left: 78.2727px; top: 478.95px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.06321);" data-canvas-width="345.96791868686853">The system monitors nation-wide reported number of deaths</div><div style="left: 78.2727px; top: 493.445px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.976696);" data-canvas-width="343.87832676767664">(population size 2014: 16.8 million) from all causes, as cause of</div><div style="left: 78.2727px; top: 507.94px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.955507);" data-canvas-width="343.26598762626236">death information is not available real-time. Data is received from</div><div style="left: 78.2727px; top: 522.435px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00147);" data-canvas-width="199.50920959595962">Statistics Netherlands by weekly emails.</div><div style="left: 78.2727px; top: 550.018px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.07424);" data-canvas-width="50.65042676767676">Methods</div><div style="left: 91.3182px; top: 563.021px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01513);" data-canvas-width="329.5973952020201">Once a week the number of reported deaths is checked for excess</div><div style="left: 78.2727px; top: 577.516px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01539);" data-canvas-width="342.645023989899">above expected levels at 2 different time-lags: within 1 and 2 weeks</div><div style="left: 78.2727px; top: 592.011px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.938307);" data-canvas-width="343.23272171717156">after date of death (covering a median 43% and 96% of all deaths</div><div style="left: 78.2727px; top: 606.506px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02526);" data-canvas-width="343.0171093434343">respectively). A weekly email bulletin reporting the findings is sent</div><div style="left: 78.2727px; top: 621.001px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.993557);" data-canvas-width="341.9821699494948">to the Infectious Disease Early Warning Unit (at CIb) and a summary</div><div style="left: 78.2727px; top: 635.496px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.978105);" data-canvas-width="341.65197499999977">of results is posted on the RIVM website (National Institute for Public</div><div style="left: 78.2727px; top: 649.991px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03778);" data-canvas-width="343.29678939393926">Health and the Environment). Any known concurrent and possibly</div><div style="left: 78.2727px; top: 664.485px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03652);" data-canvas-width="343.24257828282845">related events are also reported. When excess deaths coincide with</div><div style="left: 78.2727px; top: 678.98px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.03081);" data-canvas-width="342.95057752525247">hot temperatures, the bulletin is sent to the Heat Plan Team (also at</div><div style="left: 78.2727px; top: 693.475px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.959408);" data-canvas-width="343.40397954545466">RIVM). Data are also sent to EuroMOMO which monitors excess</div><div style="left: 78.2727px; top: 707.97px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.952204);" data-canvas-width="343.3965871212119">mortality at a European level. For the Dutch system baselines and</div><div style="left: 78.2727px; top: 722.465px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01035);" data-canvas-width="344.6804047979795">prediction limits are calculated using a 5 year historical period</div><div style="left: 78.2727px; top: 736.96px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.964201);" data-canvas-width="343.0787128787878">(updated each July). A serfling-like algorithm based on regression</div><div style="left: 78.2727px; top: 751.455px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.985775);" data-canvas-width="341.60392424242417">analysis is used to produce baselines which includes cyclical seasonal</div><div style="left: 78.2727px; top: 765.95px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00043);" data-canvas-width="342.2482972222223">trends (models based on historical data in which weeks with extreme</div><div style="left: 78.2727px; top: 780.445px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.963548);" data-canvas-width="343.50500934343427">underreporting have been removed. Also periods with high excess</div><div style="left: 78.2727px; top: 794.94px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0102);" data-canvas-width="342.491015151515">mortality in winter and summer were removed so as not to influence</div><div style="left: 78.2727px; top: 809.435px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00139);" data-canvas-width="187.17618181818185">the baseline with previous outbreaks).</div><div style="left: 78.2727px; top: 837.018px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.08542);" data-canvas-width="44.50239393939395">Results</div><div style="left: 91.3182px; top: 850.021px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01324);" data-canvas-width="329.6405176767677">Increased mortality occurred during the entire influenza epidemic</div><div style="left: 78.2727px; top: 864.516px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02828);" data-canvas-width="343.0010924242425">and up to three weeks thereafter (weeks 1-14 of 2016), except for a</div><div style="left: 78.2727px; top: 879.011px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04014);" data-canvas-width="343.02080555555574">drop in week 7 (figure1). Excess mortality was primarily observed</div><div style="left: 78.2727px; top: 893.506px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02276);" data-canvas-width="342.7620707070707">in persons 75 or older. Additionally, in several weeks mortality was</div><div style="left: 78.2727px; top: 908.001px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.0424);" data-canvas-width="343.0700883838383">increased in 65-74 year olds, (weeknr 4-6; peaking in week 4 with</div><div style="left: 78.2727px; top: 922.496px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00023);" data-canvas-width="344.27751767676784">564 deaths, when 468 baseline deaths were predicted). Also, in</div><div style="left: 78.2727px; top: 936.991px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02695);" data-canvas-width="342.9850755050504">week 4, mortality in the 25-34 year-old age group was significantly</div><div style="left: 78.2727px; top: 951.485px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.975219);" data-canvas-width="341.92795883838374">increased (25 deaths, while 14 were expected as baseline). Cumulative</div><div style="left: 78.2727px; top: 965.98px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.99452);" data-canvas-width="344.35267398989896">excess mortality was estimated at 3,900 deaths occurring during</div><div style="left: 78.2727px; top: 980.475px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.990095);" data-canvas-width="344.43768686868685">the 11 weeks of the 2015/2016 influenza epidemic and at 6,085</div><div style="left: 78.2727px; top: 994.97px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.998283);" data-canvas-width="342.21133510101004">during the total winter season (44 weeks running from week 40 up to</div><div style="left: 78.2727px; top: 1009.47px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.00132);" data-canvas-width="48.58054797979798">week 20).</div><div style="left: 443.545px; top: 309.402px; font-size: 12.3207px; font-family: sans-serif; transform: scaleX(1.10408);" data-canvas-width="73.93656313131314">Conclusions</div><div style="left: 456.591px; top: 322.405px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.969953);" data-canvas-width="330.9157108585858">In terms of number of deaths during the winter season (weeks</div><div style="left: 443.545px; top: 336.9px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.974713);" data-canvas-width="341.65320707070697">40-20) and during the influenza epidemic (weeks 1-11), the 2015/2016</div><div style="left: 443.545px; top: 351.395px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.975052);" data-canvas-width="341.56080176767676">season in the Netherlands was of moderate severity compared with the</div><div style="left: 443.545px; top: 365.89px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02176);" data-canvas-width="342.79903282828275">previous five years (and was of similar magnitude as the 2011/2012</div><div style="left: 443.545px; top: 380.384px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.04643);" data-canvas-width="343.3165025252523">winter). Notable was the short three-week time span with a higher</div><div style="left: 443.545px; top: 394.879px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.998344);" data-canvas-width="342.2322803030302">peak in mortality in 65-74 year olds than has been observed in recent</div><div style="left: 443.545px; top: 409.374px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.980146);" data-canvas-width="344.0803863636366">years. Although the influenza epidemic reached its peak in week</div><div style="left: 443.545px; top: 423.869px; font-size: 12.3207px; font-family: serif; transform: scaleX(0.954067);" data-canvas-width="343.7822252525253">7, the mortality data showed a dip in week 7. The reason for the</div><div style="left: 443.545px; top: 438.364px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.02052);" data-canvas-width="342.8421553030301">temporary decrease is unknown but there was a partial overlap with</div><div style="left: 443.545px; top: 452.859px; font-size: 12.3207px; font-family: serif; transform: scaleX(1.01134);" data-canvas-width="82.47481313131313">a public holiday.</div>}, number={1}, journal={Online Journal of Public Health Informatics}, author={de Lange, Marit and Teirlinck, Anne and Dijkstra, Frederika and Stoeldraijer, Lenny and Harmsen, Carel and van der Hoek, Wim}, year={2017}, month={May} }