1443. Estimation of Impact of Potential Anti-staphylococcal Vaccination on Hospital Length of Stay.
Session: Poster Abstract Session: HAI: Surgical Site Infections
Friday, October 28, 2016
Room: Poster Hall

Background:

Staphylococcus aureus surgical site infections (SSI) induce complications leading to increase hospital length of stay (LOS) and additional costs. Patients undergoing total hip arthroplasties (THA) could be a good target population for prevention of S. aureus SSI by vaccine. Our objective was to assess the reduction in LOS due to a potential anti-staphylococcal vaccination according to the number of patients to vaccine and for different theoretical vaccine efficacies (VE).

Methods:

We used THA data from the national surveillance network of the SSI in South-East of France between 2008-2011. The outcome was the occurrence of a deep SSI infection with S. aureus within 30 days after surgery. Reduction in LOS after virtual vaccination was estimated by simulation. One group of patients was sampled with replacement 10,000 times. After virtual vaccination, infection status in this group was drawn from a binomial distribution depending on the VE. The LOS of “no more infected patients” was randomly drawn from the matched stratum (Gender/ National Nosocomial Infection Surveillance index/ multiple procedure / 5-years age category) of non-infected patients from the total population. The reduction in LOS was the difference of LOS for each patient for which infection status has changed after vaccination. Simulations were repeated for VE ranging from 20%-100% by step of 20% and for 5 sample sizes ranging from 500 to 8,000 patients.

Results:

18,674 patients older than 50 years and undergoing THA were included, 52 (2.8‰) deep S. aureus SSI occurred. Main results are given table 1. With a VE of 80% and 2,000 patients to vaccine, the cumulative reduction in LOS would be of 49.7 days.

Table 1. Mean reduction in hospital length of stay (days) after virtual anti-staphylococcal vaccination according to vaccine efficacy and sample size

 

 

Number of individuals to vaccine

VE (%)

500

1000

2000

4000

8000

20

2.03

6.36

12.9

23.3

46.0

40

4.39

12.7

25.1

45.3

92.5

60

6.50

18.7

37.0

70.2

138

80

8.58

25.8

49.7

93.6

183

100

10.6

32.0

62.3

116

229

Conclusion:

This method of simulation could be a useful tool for estimating reduction in LOS due to anti-staphylococcal vaccination in surgery. Vaccination impact might be compared to current preventive measures for SSI control policies.

 

Marie-Paule Gustin, PharmD, PhD1,2,3, Robin Ohannessian, MPH3, Marine Giard, MD3,4, Emmanuelle Caillat-Vallet, MD4, Thomas Bénet, MD1,3, Anne Savey, MD3,4 and Philippe Vanhems, MD, PhD1,2,3, (1)Infection Control and Epidemiology Unit, Edouard Herriot Hospital, Hospices Civils de Lyon, Lyon, France, (2)Innovative Clinical Research Network in VACcinology (iREIVAC), Lyon, France, (3)International Center for Infectiology Research (CIRI), Laboratory of Emerging Pathogens, UCBL1, Lyon, France, (4)Coordination Center for Healthcare Associated Infection Prevention and Control in South-East of France (CCLIN Sud-Est), Saint Genis Laval, France

Disclosures:

M. P. Gustin, None

R. Ohannessian, None

M. Giard, None

E. Caillat-Vallet, None

T. Bénet, None

A. Savey, None

P. Vanhems, None

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.