Fully injection molded test swabs enter human trials for COVID-19

The new swabs are fully injection molded and feature a flexible, honey dipper-like design that allows them to collect a sample from a patient’s nasopharynx effectively and comfortably. Photo Credit: Wyss Institute at Harvard University

An injection molded plastic test swab with a corkscrew-like tip could help address the global shortage of swabs needed for COVID-19 testing and research.

Researchers at the Wyss Institute at Harvard University in Boston, Mass., in collaboration with health care, research, and industrial partners, have designed the new nasopharyngeal swab, and the benefit is that it can be manufactured quickly and inexpensively at high volume.

The swabs are currently in human trials at SUNY Downstate Medical Center and Translational Genomics Arch Institute (TGen), an affiliate of City of Hope, and in preclinical evaluation at six U.S. hospitals; and according to the Harvard Gazette, the goal is to have California-based medical device manufacturer IPB Inc. producing up to 200,000 swabs per day by May 15.

Nasopharyngeal swabs have been used in hospitals for more than 50 years, and traditionally consist of two pieces: an injection molded plastic handle and an absorptive tip made of a soft material such as cotton, polyester, or flocked nylon. Each swab is manufactured in a multi-step process, then assembled, sterilized, and packaged, all of which requires significant time and expense. As part of the overall effort to create a more streamlined alternative, other teams have leveraged 3D printing to meet this challenge, which has led to some useful short-term solutions. However, 3D printing is costly and slow compared to injection molding – which is why the Wyss team set out to create a new design that could be injection molded as opposed to 3D printed,

The swabs currently being tested in hospitals and health centres were injection molded by prototype molder Protolabs, of Maple Plain, Minn., with a medical-grade polypropylene co-polymer.

“Experts have recently estimated that the United States needs to more than triple the number of daily COVID-19 tests in order for the country to be safely reopened by mid-May, but the current swabs are complicated to make, and producers just don’t have the ability to increase production to that level in such a short period of time,” said Richard Novak, Ph.D., a Senior Staff Engineer at the Wyss Institute. “These new swabs can help meet the critical need for collecting samples, both to diagnose patients and to study the virus itself so that treatments and a vaccine can be found sooner.”