Question

please give a detailed description of these data found on this page. ( this article is talking about the epidemic intensity during the 1918 influenza pandemic)

thank you

Table 1. Summary of interventions and their timing across 17 cities Median interquartierangel epidemic stage ICEPID) at time of implementation 5.6 3.1. 25.50 Number of 17 cities implementing Death Rate 100.000 Population Intervention 150706.30.3) Fig. 1 Excess mortality over 1913-1917 baseline in Philadelphia and St. Louit September 8-December 21, 1918. Data are derived from ref. 10. 30.8 (15.1 .3) 29.9 1124, 110.6) 299 (10.3. 66.9) 467 (124) 84.7029.. 322.00 the date on which the intervention was announced. Thus, early interventions in a given city were those that were implemented when relatively few individuals had died, whereas later ones Making influenza a notifiable disease Emergency declarations Isolation policies Quarantine of households where infection Identified School closures Church closures Theater closures Dance hall closures Other closures Staggered business hours to reduce congestion in stores and on transit systems Mask ordinances Rules forbidding crowding on streetcars Private funerals Bans on door-to-door sales Interventions designed to reduce transmission in the workplace Protective sequestration of children Bans on public gatherings No-crowding rules in locations other than transit systems Community-wide business closures 92.110.8. - poweyeces al death 30.8 (12.4, 118.1) 4 + school churches mes e s cosed closed CEHO <10 CEPID <30 CEPID30 CEPO theater closed CEPID430 public gathering barned CEPI-30 Shown only for interventions Implemented in at least nine cities 50% 75th percentile not shown for interventions implemented in <13 cities. tions are included in supporting information (SI) Appendal. We then related this information to the observed outcomes of the peak weekly death rate and CEPID during the period September December, 1918. Excess death rates were used as a proxy for case incidence because of the more accurate reporting of deaths than cases. We hypothesized that early implementation of multiple NPIS in an immunologically nalve population would slow the progression of the epidemic, resulting in a flatter epidemic curve, but that over time aggregate outcomes would approach those observed in cities not implementing such measures, until roughly comparable levels of herd immunity were achieved. pl study periodo Padeath rate median for en Results Effect of Early Interventions on Epidemic Spread. We assessed the relationship between the timing of NPls and three measures of epidemic outcome: (1) the peak weekly rate of excess P& deaths per 100,000 population (peak death rate) during the study period; (i) the "normalized" peak weekly excess P&I death rate (peak weekly death rate during the study period divided by the median weekly rate during the period); and (ii) the CEPID per 100,000 population during the study period. The tee of the epidemic at the time of each intervention was defined as the CEPID from the start of the study period until 5+ school churches public m es measures osed closed dose gatherings CEPD. CEPID CEP 30 CEPOS CEPID30 Banned CEPO Fig. 2. Relationship of a peak weekly excess P&I death rate and (b) total excess P&I death rate during the study period to the timing of varius Nis Cities were divided evenly into those intervening early black basso not at all gray bars, and the median outcome for the early and late groups was plotted. The first two groups of bars assess overall timing of intervention comparing those cities that announced four or more N Pls before experiencing 20/100,000 CEPID with those with three or fewer and those that announced five or more is before experiencing 10/100,000 CPD with those with four or fewer. The remaining groups compare those cities that announced partic war mere before experiencing 30/100,000 CEPID with these the Sgnificance by Mann-Whitney U test: P<0.05. Watchet et al PNAS M

Answer 1

We noted that, in some cases, outcomes appear to have correlated with the quality and timing of the public health response. The contrast of mortality outcomes between Philadelphia and St. Louis is particularly striking (Fig. 1). The first cases of disease among civilians in Philadelphia were reported on September 17, 1918, but authorities downplayed their significance and allowed large public gatherings, notably a city-wide parade on September 28, 1918, to continue. School closures, bans on public gatherings, and other social distancing interventions were not implemented until October 3, when disease spread had already begun to overwhelm local medical and public health resources. In contrast, the first cases of disease among civilians in St. Louis were reported on October 5, and authorities moved rapidly to introduce a broad series of measures designed to promote social distancing, implementing these on October 7. The difference in response times between the two cities (≈14 days, when measured from the first reported cases) represents approximately three to five doubling times for an influenza epidemic. The costs of this delay appear to have been significant; by the time Philadelphia responded, it faced an epidemic considerably larger than the epidemic St. Louis faced. Philadelphia ultimately experienced a peak weekly excess pneumonia and influenza (P&I) death rate of 257/100,000 and a cumulative excess P&I death rate (CEPID) during the period September 8–December 28, 1918 (the study period) of 719/100,000. St. Louis, on the other hand, experienced a peak P&I death rate, while NPIs were in place, of 31/100,000 and had a CEPID during the study period of 347/100,000. Consistent with the predictions of modeling, the effect of the NPIs in St. Louis appear to have had a less-pronounced effect on CEPID than on peak death rates, and death rates were observed to climb after the NPIs were lifted in mid-November (7 ⇓–9).

In comparisons across cities (Fig. 2 a, Table 2), we found that aggressive early intervention was significantly associated with a lower peak of excess mortality (Spearman ρ = −0.49 to −0.68, P = 0.002–0.047; see Table 2, Number of interventions before, for the number of NPIs before a given CEPID cutoff vs. peak mortality). Cities that implemented three or fewer NPIs before 20/100,000 CEPID had a median peak weekly death rate of 146/100,000, compared with 65/100,000 in those implementing four or more NPIs by that time (Fig. 2 a, P = 0.005). The relationship was similar for normalized peak death rates and for a range of possible cutoffs (see Table 2, CEPID at time of intervention), although the relationship became weaker as later interventions were included. Cities with more early NPIs also had fewer total excess deaths during the study period (Fig. 2 b, Table 2, 1918 total), but this association was weaker: cities with three or fewer NPIs before CEPID = 20/100,000 experienced a median total excess death rate of 551/100,000, compared with a median rate of 405/100,000 in cities with four or more NPIs (P = 0.03).