## Facts

- Rolf and Angela Hazlehurst filed a Vaccine Act petition on behalf of their minor son, William Yates Hazlehurst, seeking compensation for alleged vaccine-related injury.
- Yates received the MMR vaccine in February 2001, shortly before his first birthday.
- Petitioners asserted Yates developed normally before vaccination and later developed developmental and gastrointestinal problems, with an autism diagnosis in July 2002.
- The claim alleged that MMR, alone or in combination with thimerosal-containing vaccines, caused “regressive autism” through immune dysfunction, persistent measles virus, and resulting inflammation affecting the gastrointestinal system and brain.
- The case served as a test case in the Omnibus Autism Proceeding addressing the combined MMR/thimerosal causation theory.
- A special master denied compensation, finding petitioners failed to prove causation; petitioners moved for review in the Court of Federal Claims.

## Issues

1. Whether the special master committed reversible error by admitting and relying on evidence developed in other litigation and produced shortly before the hearing.
2. Whether the special master reversibly erred by failing to consider or discuss additional evidence offered by petitioners.
3. Whether the special master erred by declining to decide whether regressive autism is a distinct phenotype from classic autism.
4. Whether the special master’s causation findings under the Vaccine Act were arbitrary, capricious, or not in accordance with law under the preponderance standard and the Althen causation-in-fact framework.

## Decision

- The Court of Federal Claims denied the motion for review and affirmed the special master’s decision denying compensation.
- The court held the special master acted within her discretion in considering evidence from other litigation and the timing of its introduction did not render the proceeding unfair.
- The court held the special master was not required to discuss every item of record evidence and any allegedly omitted material would not have changed the result.
- The court held the special master did not need to resolve the regressive-versus-classic autism classification dispute because it was unnecessary to decide causation.
- The court upheld the finding that petitioners failed to establish causation because it had a rational basis in the record and applied the correct legal standards.

## Legal Principles

- On Vaccine Act review, factual findings are upheld unless arbitrary and capricious; legal conclusions are reviewed for compliance with law, with deference to the special master’s weighing of expert testimony.
- A reviewing court may not reweigh evidence; it asks whether the special master’s decision is supported by a rational basis and reflects correct legal standards.
- Special masters have broad discretion to admit relevant evidence, including materials from other proceedings, provided the process remains fair and parties have an opportunity to respond.
- Special masters need not address every piece of evidence in writing; it is sufficient that the decision shows consideration of relevant evidence and supports the outcome.
- Under Althen, petitioners must prove by a preponderance: (1) a reliable medical theory, (2) a logical sequence of cause and effect, and (3) a proximate temporal relationship; temporal association alone does not establish causation.

## Conclusion

The Court of Federal Claims affirmed the denial of Vaccine Act compensation because the special master permissibly admitted challenged evidence, was not required to decide disputed autism classifications, and reasonably found petitioners’ MMR/thimerosal causation theory unreliable and insufficient under Althen and the preponderance standard.


Hazlehurst v. Sec’y of Health & Hum. Servs., 88 Fed. Cl. 473 (2009)