Editor’s Note: This month’s article was guest co-authored by David I. Levine and Dorit R. Reiss. Both are Professors of Law at University of California Hastings College of the Law. We would like to thank them for sharing their expertise related to legal matters that may be relevant for our readers in their professional capacities.

Have you ever had to appear in court in your professional capacity? Healthcare providers can find themselves in court in their professional capacity in a few scenarios. When it comes to vaccines, these situations may include:

  • Being sued for malpractice — This is extremely rare for claims of vaccine harms, because under the National Childhood Vaccine Injury Act such claims need to go through the National Vaccine Injury Compensation Program first, but it is possible. Other malpractice claims can arise from non-vaccinating. Specifically, providers can be sued if a patient was harmed because a vaccine that should have been offered was not offered as occurred in this case.
  • Being sued around implementation of vaccine mandates — This has occurred related to influenza vaccine mandates.
  • To serve as expert witnesses — Providers may be called to serve as experts in cases like those mentioned above or in other vaccine-related cases, for example, during family disputes regarding whether or not to vaccinate.

These situations can be uncomfortable — or, in some cases, may even feel threatening. This post offers some basic information on what to expect if you find yourself in court (or a court-like setting).

Understanding the basics

In all these cases, it is important to understand some of the basics about a lawsuit. Cases such as those listed above are civil lawsuits. Civil lawsuits begin when one party (usually called the plaintiff) files a complaint against another in state or federal court. The other party (usually called the defendant) can respond to the complaint by filing one or more of the following:

  • Motions seeking to dismiss part or all of it
  • Answers responding to the facts and legal conclusions (admitting or denying them in detail)
  • Affirmative defenses, such as a claim that the complaint was filed too late to be considered

If the complaint moves past this initial stage without being dismissed, the process known as “discovery” begins. This is the period when lawyers use various legal means to uncover relevant evidence, facts and other information related to the case. This process allows the lawyers to prepare for trial, including informing their strategy related to making motions or encouraging or allowing for settlements. Discovery almost always includes the following:

  • Exchanging documents  between the parties — often includes expert reports
  • Conducting depositions of parties and witnesses — oral questioning taken under oath

After discovery is completed, it is common for a case to be settled or disposed of by motion, but this doesn’t always happen. Some claims will proceed to trial. The trial can be conducted in the presence of a judge and jury or — in some limited circumstances, or if the parties agree — before a judge alone.

The trial involves the parties presenting their evidence through oral testimony of witnesses, documents, and other approved methods. The goal of each party is the same — trying to convince the judge or jury that their version of events is more likely to be true. This standard, which is used nearly always in civil cases, is referred to as the preponderance of evidence standard. In its literal form, it means that the version of events presented must be more than 50 percent likely. During the trial, the judge rules on legal issues that arise. After both sides have presented their evidence, the judge or jury are tasked with making factual findings and applying the law to those facts.

Because the judge or jury will be left to sort out the facts in a case, persuasion matters a great deal in civil cases. During the trial, the persuasion often must be directed at the lay members of the jury. Facts need to be demonstrated through admissible evidence, and the evidence needs to be woven into a story that is convincing.

Sometimes the decision-making is straightforward. For example, a jury might have to decide whether a bicyclist or a motorist ran a red light, causing injury to the bicyclist when the two collided. Sometimes the decision-making is more complex. For example, a jury might be asked to decide whether a gardener who used a weed killer manufactured by the defendant, and who subsequently contracted a certain type of cancer, got the disease from using that product, such as recently occurred in the case against Monsanto. In such cases, the jury would be charged with weighing testimony from experts on the relevant scientific questions. Sometimes, this means that decisions are not entirely supported by scientific evidence, particularly in jury-decided cases. This may happen if the science is not certain, but sometimes it can occur if the experts presented by the side challenging the science were more convincing. This is one reason why expert witnesses are important; part of their job is to educate a court about good versus bad science. This is also an important reason why healthcare providers answering vaccine safety questions on the frontlines should be able to describe to parents or concerned family members why rulings in court cases should not be considered as evidence of scientific causality: the standards are different, and the legal conclusion may not match what science has shown.

The role of experts

Experts are needed every time a case involves matters that are beyond the knowledge of a lay person. It is a crucial role — in many cases, not having an appropriate expert can mean losing the case, and the expert’s credibility makes an enormous difference.

Rule 702 of the federal rules of evidence sets out a common standard establishing when expert testimony is appropriate and the criteria by which courts assess it. Until the 1990s, expert testimony was assessed by the Frye standard, from Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). Frye, in essence, left the decision to the scientific community. This meant that if the methods and standards used by an expert witness were deemed reliable by at least part of the scientific community, the testimony was admissible. However, this standard changed in the 1990s. After the U.S. Supreme Court’s adoption of the Daubert standard (set out in Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993) and its progeny), whether the expert’s testimony is allowed is determined by the court, and it can only be allowed if it is reliable based on several specific factors. Daubert essentially made courts the gatekeepers of which scientific evidence and expert testimony can or cannot be brought into court. In practice, it means less expert testimony is admissible than under the more forgiving Frye standard.

Often, but not always, an expert will be required to submit a written report. The report typically includes the opinions the expert will provide during testimony, the data and materials that support the opinions, the expert’s qualifications (including publications), other cases in which the expert testified, and what the expert is paid for testifying. 

Regardless of whether experts have to write a report, they should expect to be deposed and questioned about what they say, the basis for their conclusions, their qualifications, and any potential conflicts of interests. Anyone called to be an expert should prepare for all these issues.

An expert’s best source for what to expect, what to focus on, and the preparation required should be the lawyer who has engaged the expert. After all, the lawyer has an interest in helping the expert be well-prepared and must be familiar with the rules for the jurisdiction and the information related to the specific proceeding. Interactions between the lawyer and the expert may (or may not) be protected from disclosure, so the expert needs to know what the parameters are in a particular case. However, the expert is also likely to have information that will help the lawyer. After all, the expert is engaged in part because of her knowledge related to the topics relevant in the case and can help the lawyer understand the materials and prepare for various parts of the proceedings. The below resources offer a few links to expert preparation guides. However, this really is an area where it’s advisable to be guided by the lawyer you are working with. If an expert cannot trust the hiring lawyer, they should likely not serve in the case.

It’s also important to realize that experts have some rights in this process. Under rule 26 (b)(4)(E)(i) of the federal rules of civil procedure, the other side is expected to pay the expert “a reasonable fee” for time spent responding to discovery (whether preparing materials or in deposition). And, under rule 30 (d), the duration of a deposition is usually limited to one day of seven hours, and a party can ask to terminate a deposition that “is being conducted in bad faith or in a manner that unreasonably annoys, embarrasses, or oppresses the deponent or party.” Many states have parallel rules; again, the lawyer who engaged you should be your guide and protector in this regard.

Court proceedings can be challenging. However, we hope that the information provided in this article can help should you ever find yourself in such a situation.


Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.