Group B streptococcal late-onset sepsis — leading natural cause of preterm collapse
The prosecution’s claim: Sudden deteriorations in the indicted infants were framed as anomalous and as requiring a deliberate-act explanation.
Prosecution claim
Sudden deteriorations in the indicted infants were framed as anomalous and as requiring a deliberate-act explanation.
Counter-evidence
Group B Streptococcus (GBS) is colonised in 10-30% of pregnant women in the UK. Late-onset GBS sepsis (>72 hours of life) is the leading cause of unexpected collapse and mortality in preterm neonates beyond the early-onset window. Presentation is characteristically sudden — apnoea, bradycardia, circulatory collapse — and frequently mimics the deterioration trajectory the prosecution attributed to deliberate harm. Without paired blood-culture and PCR investigation taken at the moment of collapse (which is methodologically difficult mid-resuscitation), late-onset GBS sepsis is routinely missed and attributed to other causes after the fact. Independent paediatric review has flagged the GBS differential across multiple Letby counts.
Key point: Sudden apnoea and circulatory collapse in a preterm neonate beyond 72 hours of life is most commonly late-onset sepsis until proven otherwise. Group B Strep is the leading single organism. Reaching past it for a deliberate-act explanation requires positive evidence — not merely the absence of a confirmatory blood culture.
What the jury heard
Infection differentials were referenced selectively. The leading-cause status of late-onset GBS sepsis in unexpected preterm collapse — and the methodological difficulty of catching it on culture mid-resuscitation — was not foregrounded.
What the Panel says
Infection is central to the Panel's findings, though not in the form of a GBS diagnosis. The Panel attributes Child D's death to systemic sepsis, pneumonia and DIC; Child G's deterioration to infection, possibly enterovirus; Child J's deterioration on day 47 to sepsis; Child M's apnoea to sepsis or the eustachian valve; Child Q's picture to early NEC or sepsis; and Child I's death to respiratory complications complicated by an untreated Stenotrophomonas maltophilia colonisation. GBS itself is not something the Panel diagnoses — it is one of the infective differentials the original investigation never ruled out.
What independent experts add
- Dr Peter Donnelly's microbiological commentary covers the broader infection-control and unit-environment picture.
- GBS prevalence in UK maternity populations is documented in UK Health Security Agency surveillance reports.