Reaction profile
The FDA adverse-event record for lack of efficacy (bacteria) - histophilus somni
48 FDA reports name lack of efficacy (bacteria) - histophilus somni, a lower-volume reaction in the CVM extract (VeDDRA 2993). Plate stamps and neighbourhood peers follow.
- #1758 of 2,481
- by report volume (all reactions)
- 48
- reports citing this reaction
- 87.5%
- death-coded share
- Cattle
- most-affected species
Release-over-release change
What changed in the latest FDA data snapshot
PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Lack of efficacy (bacteria) - Histophilus somni has 48 reports now versus 46 in that prior snapshot: 2 more (4.3%).
- Report change
- +2
- Death-coded reports
- +2
- Death-coded share
- +0.5 pts
This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.
Subscribe to Lack of efficacy (bacteria) - Histophilus somni changesFDA AER · VeDDRA plate
Code 2993 VOL-TRACE
VOL-TRACE · DEATH-HOT · MID-PACK · PHOTO-FINISH · SPECIES-CATTLE · DRUG-LEAD · DESK-MID · BOOK-FULL
- VOL-TRACE 48 reports
- DEATH-HOT 87.5%
- MID-PACK #1758/2481
- PHOTO-FINISH Abnormal echocardiogr…
- SPECIES-CATTLE Cattle · 48
- DRUG-LEAD Tulathromycin · 25
- DESK-MID 6 breeds
- BOOK-FULL 8/8 fields
Nearest volume peer: Abnormal echocardiogram (±0 reports)
Upper-third death-coded share drives the outcome stamps on this plate; volume band, corpus rank, and co-report peers follow. Not a clinical diagnosis.
Lower-volume neighbourhood around Lack of efficacy - Histophilus somni
Lower-third volume poles plus nearest peers, not a full reaction corpus board reprint.
Lack of efficacy (bacteria) - Histophilus somni: high death-coded share in the FDA AER plate
Signature read: Lack of efficacy (bacteria) - Histophilus somni's 87.5% death-coded share is among the highest in the openFDA reaction corpus. Report volume is lower-third scale: 48 named reports in the openFDA extract. Death-coded share is upper-third: 42 of 48 reports (87.5% of named reports). Nearest volume peer: Abnormal echocardiogram (±0 reports). Lead species Cattle (48). Lead co-reported drug Tulathromycin (25).
Read these counts as reporting volume, not risk: per our methodology, A high death-coded share in FDA filings does not prove causation; co-reporting is voluntary temporal association only. Browse the full reactions index or the about page for how PlainBreed frames FDA CVM extracts.
Species Most Affected
Breeds Most Affected
Associated Drugs
What to do with this reaction
- Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
- Browse the full reaction directory to compare report counts across reaction types. All reactions
A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.
Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025
Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →