Service connection
How do direct, secondary, presumptive, and aggravation service connection differ?
Service connection is VA’s recognition that a disability is linked to military service under an applicable legal pathway. Direct service connection generally focuses on a current disability, an in-service event or disease, and a link between them. Secondary service connection addresses a new disability caused or aggravated by an already service-connected disability. Presumptive service connection uses laws or regulations that supply the service link when the stated service and condition requirements are met. Aggravation can also apply when service worsened a pre-existing condition or when a service-connected disability worsens another condition.
What is direct service connection?
VA describes eligibility for an in-service disability claim when a Veteran became sick or injured while serving and can link the current condition to that illness or injury. Evidence can include service records, medical records, medical opinions, and competent lay evidence depending on the fact being established.
Direct service connection is not limited to conditions diagnosed during service. The evidence may support a post-service diagnosis when the record establishes the required relationship.
How do VA secondary conditions work?
A secondary service-connected claim is for a new disability linked to a disability VA has already determined is service connected. VA’s evidence guidance says the record generally needs to show the new condition and the link between it and the service-connected disability.
Under 38 CFR § 3.310, secondary service connection can also involve aggravation when a service-connected condition causes an increase in severity of another disability, subject to the regulatory requirements.
What is presumptive service connection?
For certain conditions and service circumstances, law or regulation allows VA to presume the service relationship. When the Veteran meets the applicable service and condition requirements, the Veteran generally does not have to separately prove that military service caused the presumptive condition.
Presumptions vary by exposure, location, era, diagnosis, timing, and other criteria. A condition appearing on a list does not by itself prove that every Veteran meets the service requirements.
What is aggravation service connection?
Aggravation can refer to a condition that existed before service and became worse during service beyond the applicable legal standard, or to a non-service-connected disability that is worsened by an already service-connected disability.
The evidence and legal standard differ between these situations. VMC should not infer aggravation merely because two conditions coexist or worsened over time.
Official sources
- VA: Eligibility for disability benefits ↗
- VA: Evidence needed for a disability claim ↗
- VA: Types of disability claims and when to file ↗
- 38 CFR § 3.303 — Principles relating to service connection ↗
- 38 CFR § 3.306 — Aggravation of preservice disability ↗
- 38 CFR § 3.310 — Secondary conditions and aggravation ↗