To screen or not to screen

ANTENATAL SCREENING

Jim GrayConsultant Microbiologist

Birmingham Women’s HospitalJames.gray@bwnft.nhs.uk

Overview

• Current infection screening arrangementso National Screening Committee Programmeo Other

• How screening might change• Future research opportunities

To Screen or Not to Screen

Antenatal screening

Stakeholders• National Screening

Committee• Department of Health• Public Health England• NICE• RCOG

NHS Infectious Diseases in Pregnancy Screening Programme

Uptake >97%• 1,749/688,755 (0.25%) HIV-positive• 3,982/690,760 (0.58%) hepatitis B positive• 944/678,611 (0.14%) syphilis-positive• 44,650/677,479 (6.59%) rubella non-immune

Infection screening in pregnancy

NSC Infectious Diseases in Pregnancy Screening Programme• HIV• Hepatitis B• Syphilis• Rubella immunity

NSC endorsed screening• Asymptomatic bacteriuria

Other screening• Chlamydia• GBS• AMR bacteria

NHS Infectious Diseases in Pregnancy Screening Programme (2013)

Uptake >97%• 1,749/688,755 (0.25%) HIV-positive• 3,982/690,760 (0.58%) hepatitis B positive• 944/678,611 (0.14%) syphilis-positive• 44,650/677,479 (6.59%) rubella non-immune

HIV screening

AIM• To prevent paediatric HIV infectionOBJECTIVES• To identify all HIV positive women• To ensure the rapid referral of all HIV positive

women for assessment and management within a multi-disciplinary team

Hepatitis B screening

AIM• To prevent perinatal hepatitis B infectionOBJECTIVES• To ensure all hep B +ve women are identified• To ensure all hep b +ve women are referred for

specialist assessment and management within 6 weeks

• To ensure infants are appropriately vaccinated; 1st dose within 24 h & schedule completed

Syphilis screening

AIM• To prevent congenital syphilis infectionOBJECTIVES• To identify all women with positive syphilis

screening test results early in pregnancy• To ensure their rapid assessment by an

appropriate specialist, e.g. GUM within a multi-disciplinary environment

Rubella screening

AIM• To reduce the risk of congenital rubella in future

pregnanciesOBJECTIVES• To ensure all women susceptible to rubella infection

(<10 IU/ml) are identified• To ensure these women are offered postnatal MMR• To ensure that the 1st dose is administered prior to

discharge from maternity services, & the GP is contacted regarding the 2nd dose

How accurate is rubella immunity screening? UK NEQAS distribution 3148

Method Range Median 5-95%

Abbott Architect 7-30 8 7-10

Abbott AxSYM 8-34 12 9-22

Beckman Access 12-18 14 12-17

Biokit Bioelisa 7-28 14 8-19

bioMerieux Vidas 1-23 17 14-19

DiaSorin 7-11 9 8-11

DiaSorin Liaisaon 5-11 8 6-11

OCD Vitros 9-12 10 9-12

Roche 12-230 194 179-222

Siemans Immunlite 12-33 13 12-25

Siemans ADVIA 29-43 34 29-41

Siemens EIA 9-28 12 10-21

ALL METHODS 12

How accurate is rubella immunity screening? UK NEQAS distribution 3148

Method Range Median 5-95%

Abbott Architect 7-30 8 7-10

Abbott AxSYM 8-34 12 9-22

Beckman Access 12-18 14 12-17

Biokit Bioelisa 7-28 14 8-19

bioMerieux Vidas 1-23 17 14-19

DiaSorin 7-11 9 8-11

DiaSorin Liaisaon 5-11 8 6-11

OCD Vitros 9-12 10 9-12

Roche 12-230 194 179-222

Siemans Immunlite 12-33 13 12-25

Siemans ADVIA 29-43 34 29-41

Siemens EIA 9-28 12 10-21

ALL METHODS 12

How accurate is rubella immunity screening? UK NEQAS distribution 3148

Method Range Median 5-95%

Abbott Architect 7-30 8 7-10

Abbott AxSYM 8-34 12 9-22

Beckman Access 12-18 14 12-17

Biokit Bioelisa 7-28 14 8-19

bioMerieux Vidas 1-23 17 14-19

DiaSorin 7-11 9 8-11

DiaSorin Liaisaon 5-11 8 6-11

OCD Vitros 9-12 10 9-12

Roche 12-230 194 179-222

Siemans Immunlite 12-33 13 12-25

Siemans ADVIA 29-43 34 29-41

Siemens EIA 9-28 12 10-21

ALL METHODS 12

Rubella screening

• Screening for rubella susceptibility does not meet the UK NSC criteria for a screening programme.

• The IDPS programme is currently working collaboratively with the PHE Immunisation team and plan to cease antenatal screening for rubella susceptibility. The present arrangements for antenatal screening and post-partum immunisation will continue until other arrangements are in place.

Screening for asymptomatic bacteriuria

External review of screening for ASB in pregnancy for the UKNSC July 2011• Policy should continue but justification changed from

prevention of preterm delivery to prevention of pyelonephritis

• Not clear whether the test should use culture

NICE CG62: Antenatal care for uncomplicated pregnancies

Women should be offered routine screening for asymptomatic bacteriuria by midstream urine culture early in pregnancy. Identification and treatment of asymptomatic bacteriuria reduces the risk of pyelonephritis.

Asymptomatic bacteriuria in pregnancy

• Symptomatic UTI in pregnancy is frequently preceded by asymptomatic bacteriuriao Prevalence is around 5%o Untreated, at least 30% of women with ASB will develop

acute pyelonephritis

• Screening for ASB is considered to be a cost effective approach to preventing pyelonephritis

A screening programme may prevent 6480 cases of pyelonephritis per year

Asymptomatic bacteriuria in pregnancyMany research questions

• What is the clinical & cost effectivness of screening?

• How should screening be undertaken?• When should screening be undertaken?• How should women with ASB be monitored during

their pregnancy?

Until it is clear that antenatal screening for GBS carriage does more good than harm and that the benefits are cost-effective, the National Screening Committee does not recommend routine screening in the UK.

Is this statement not also true of the antenatal ASB screening?

ASB screening – where does this leave us?

• Culture is said to be more accurate than dip testing, but we don’t know whether dip testing is accurate in identifying women at risk of PN

• We don’t know what the impact of ASB screening is on antibiotic use antenatallyo Too much? (because we treat people who don’t need

treatment)o Too little? (because without coordinated arrangements

to oversee patient management there is no assurance that all women with ASB receive treatment )

Other NICE recommendations

Chlamydia trachomatis• At the booking appointment, healthcare

professionals should inform pregnant women younger than 25 years about the high prevalence of chlamydia infection in their age group, and give details of their local National Chlamydia Screening Programme.

• Chlamydia screening should not be offered as part of routine antenatal care.

More NICE recommendations

Do not screen for:• Bacterial vaginosis• CMV• Hepatitis C• Toxoplasmosis• Group B Streptococci (GBS)

The Prevention of Early-onset Neonatal Group B Streptococcal DiseaseRCOG Green–top Guideline No. 36

Until it is clear that antenatal screening for GBS carriage does more good than harm and that the benefits are cost-effective, the National Screening Committee does not recommend routine screening in the UK.

The Prevention of Early-onset Neonatal Group B Streptococcal DiseaseRCOG Green–top Guideline No. 36

IAP offered to:• Women with a previous baby with neonatal GBS

disease• Women with GBS in current pregnancy• Women who are pyrexial in labour should be

offered broad-spectrum antibiotics including an antibiotic for prevention of neonatal EOGBS disease

The Prevention of Early-onset Neonatal Group B Streptococcal DiseaseRCOG Green–top Guideline No. 36

Role of IAP unclear for:• Women with preterm labour (<37 weeks’

gestation) and prelabour rupture of membranes of any duration

• Women with preterm labour & prolonged rupture of membranes (>18 h)

What would be the aim of GBS screening?

• To prevent neonatal GBS disease by administering intrapartum antibiotic prophylxis (IAP) to mothers during labour

• To assist in ruling out infection in newborn babies with soft signs of infection

What would be the aim of GBS screening?

600,000 deliveries pa

60,000 babies treated with antibiotics

300 babies with GBS early-onset neonatal

sepsis

300 babies with non-GBS early onset sepsis

59,400 babies without infection treated with

antibiotics

ALL PREGNANT WOMEN: RISK FACTORS FOR GBS

NO80% of women

NO ANTIBIOTICS GIVEN

YES20% of women

INTRAPARTUM ANTIBIOTICS GIVEN

Only around 30% of these women will have GBS; 70% (14% of all labouring women) will receive IAP that is of no value

A small number of these women will deliver a GBS-infected baby

• Moderately complex testing with < 1 min hands-on time

• Results turnaround time 55 minutes

• Manufacturer claims 99.0% sensitivity and 92.4% specificity

Cepheid GeneXpert GBS

ALL PREGNANT WOMEN: RISK FACTORS FOR GBS

NO80% of women

NO ANTIBIOTICS GIVEN

YES20% of women

INTRAPARTUM ANTIBIOTICS GIVEN

Only around 30% of these women will have GBS; 70% (14% of all labouring women) will receive IAP that is of no value

A small number of these women will deliver a GBS-infected baby

GBS1Universal PCR screening not cost effective

GBS2

Implementation of modified admission MRSA screening guidance for NHS (2014)

• Trusts should:o Identify and screen patients in high MRSA risk

specialties, e.g. adult/paediatric ICUs, NICUs, HDUs

o Identify and re-screen any patient previously known to be MRSA positive

Public Health England: Acute trust toolkit for the early detection, management and control of carbapenemase-producing Enterobacteriaceae (CPE)

• Suspected case: a patient who, in the last 12 m, has been an inpatient in a hospital abroad or a UK hospital which has problems with spread of CPE or is a previously +ve case

• Management: take rectal swab & isolate patient (with en-suite). Apply strict standard precautions until three conseutive negative rectal swabs collected 48 h apart

Conclusions

• The UKNSC Infection Screening Programme is highly effective

• However, there is a lot of additional antenatal infection screening that is not performed in a systematic and coordinated way• If this screening is clinically- and cost-effective why

could it not be incorporated into the highly effective management arrangements that already exist for the UKNSC Programme?