Table 2.

Downstream process step recovery.

	Run	TFF1	IEX	TFF2 device type	TFF2 & sterile filtration, by qPCR	Sterile filtration, by spectrophotometry
ChAdOx2 RabG	1	85	44	Pellicon 2 Mini	53	98
	2	79	72	Pellicon 2 Mini	94	96
	3	113	65	MidiKros	119	93
ChAd63 ME-TRAP	1	80	100	Pellicon 2 Mini	59	100
	2	Not done	48	Pellicon XL50	39	48
ChAdOx1 RVF	1	101	39	MidiKros	77	76
	2	107	36	MidiKros	54	90
OVERALL		93 (79–113)	48 (36–100)	Pellicon 2 Mini	59 (53–94)	98 (96–100)
				MidiKros	77 (54–119)	90 (76–93)

Percentage product recovery at each step was calculated for consecutive individual runs with each virus. All calculations were based upon viral genome qPCR, with the exception of recovery after sterile filtration which is based upon spectrophotometry (as there is no change in buffer composition at this point).

qPCR-based results are the means of results obtained from three replicate samples, with three replicate qPCR reactions per sample. All calculations were based upon comparisons made within a single qPCR run. Apparent recoveries in excess of 100% reflect residual qPCR assay variability.

The qPCR-based results presented for TFF2 recovery were produced by comparing samples taken prior to TFF2 and from the final product (after TFF2 and sterile filtration), on the basis that product loss upon sterile filtration typically reflects aggregation as a result of poor performance of the TFF2 process. Summary results are presented as medians with ranges in brackets, and are broken down by device type for TFF2 (excluding the single run performed using a Pellicon XL50 unit).