Yes, this can be an OCD symptom. Although many people think that a ritual involves doing something, it can also involve compulsively and repeatedly not doing something due to a fear of that thing. For example, refusing to sit on a chair without a towel between it and you is probably a compulsion borne of a fear of contamination, and the towel represents either a way to not get contaminated or a way to prevent the spread of contamination to other surfaces. People with OCD may fear that without the towel, contaminants will get on them and somehow harm them, or that they will spread contaminants to others, unknowingly harming them.
Let’s separate these two issues to discuss them more in-depth. People who are afraid of contamination are, at the most basic level, worried that they will be harmed. This can come in the form of an illness or disease, or also in the form of a bad feeling. Think of this almost like “cooties”, when children touch something or someone they do not like or think is gross, they say that person or thing has cooties. Performing an action that they fear can give a person with OCD that feeling of having “cooties,” but multiplied hundreds of times.
People with OCD may also perceive that the essence of someone is on an item, and if they were to touch that item, or sit on a chair that the person sat on, that person’s essence would be on them, and they find that very uncomfortable. They do not necessarily dislike the person, it could be that they just do not know the person or where the person has been, so they think the worst about the person, such as that he or she is contaminated. They would rather sit on a towel to prevent their clothes or body from coming into direct contact with something that they find disgusting, they are unable to see the chair as just a chair that in no way can transmit anything to them. This may sound strange to people without OCD, but people with OCD often irrationally attribute good or bad feelings to different people or things and then do not want to have anything to do with the “bad people.” Their rituals are designed to protect them from any physical or mental harm or contamination, whether the ritual is doing something or the refusal to do something.