When her Danish colleagues first suggested distributing protective cloth face masks to people in Guinea-Bissau to stem the spread of the coronavirus, Christine Benn wasn’t so sure.

“I said, ‘Yeah, that might be good, but there’s limited data on whether face masks are actually effective,’” says Benn, a global-health researcher at the University of Southern Denmark in Copenhagen, who for decades has co-led public-health campaigns in the West African country, one of the world’s poorest.

That was in March. But by July, Benn and her team had worked out how to possibly provide some needed data on masks, and hopefully help people in Guinea-Bissau. They distributed thousands of locally produced cloth face coverings to people as part of a randomized controlled trial that might be the world’s largest test of masks’ effectiveness against the spread of COVID-19.

Face masks are the ubiquitous symbol of a pandemic that has sickened 35 million people and killed more than 1 million. In hospitals and other health-care facilities, the use of medical-grade masks clearly cuts down transmission of the SARS-CoV-2 virus. But for the variety of masks in use by the public, the data are messy, disparate and often hastily assembled. Add to that a divisive political discourse that included a US president disparaging their use, just days before being diagnosed with COVID-19 himself. “People looking at the evidence are understanding it differently,” says Baruch Fischhoff, a psychologist at Carnegie Mellon University in Pittsburgh, Pennsylvania, who specializes in public policy. “It’s legitimately confusing.”

To be clear, the science supports using masks, with recent studies suggesting that they could save lives in different ways: research shows that they cut down the chances of both transmitting and catching the coronavirus, and some studies hint that masks might reduce the severity of infection if people do contract the disease.

But being more definitive about how well they work or when to use them gets complicated. There are many types of mask, worn in a variety of environments. There are questions about people’s willingness to wear them, or wear them properly. Even the question of what kinds of study would provide definitive proof that they work is hard to answer.

“How good does the evidence need to be?” asks Fischhoff. “It’s a vital question.”

A medical device that is used to inject fluid into, or withdraw fluid from, the body. A medical syringe consists of a needle attached to a hollow cylinder that is fitted with a sliding plunger. The downward movement of the plunger injects fluid; upward movement withdraws fluid. Medical syringes were once made of metal or glass, and required cleaning and sterilization before they could be used again. Now most syringes used in medicine are plastic and disposable.

Another low-cost detection system has been designed to detect bleeding, pH and external pressure on the wound, by using a combination of a disposable part and a reusable part attached to a disposable bandage. All the electronics were integrated on a flexible medical tape which can be detached and reused while wireless communication is realized via an inkjet printed antenna. A smartphone can be further used to monitor wound progression regardless of the patient’s location, while healthcare providers will receive this information either via the mobile network or via the internet.

An impedimetric flexible sensor based on cupric oxide (CuO) was also reported for pH measurement. CuO is a transition metal oxide that acts as a p-type semiconductor. It is stable, environmentally friendly and enables electron transfer at low potential values. Due to these advantages, CuO was used in the fabrication this sensor. Two configurations were used, CuO nanorods and nanoflowers and the nanorod-based electrodes demonstrated higher sensitivity compared to the nanoflower-based ones. The sensors consisted in screen-printed interdigitated electrodes on flexible substrates. The sensors were tested in a narrower pH range (5–8.5) compared to other techniques, demonstrated certain stability problems and did not include a wireless transmission system. However, their flexible nature makes them promising for future studies regarding the development of portable and wearable systems.

The conventional disposable infusion set originally has a protective cover on the needle, which prevents the package and the operator from being punctured and stabbed, and is usually discarded during normal operation. In this project, we transformed such protective cover into a new type one named safety tube. The inner diameter of the safety tube is slightly larger than the outside diameter of the needle body, and the length of the tube is slightly longer than the total length of the needle head plus the needle body. There is a slit along the length from the front to the middle of the tube. The open end (front) of the tube linked with the slit is in the shape of a “V,” the end of the slit at the middle of the tube is linked with a rectangular hole, and the joint is in the shape of an inverted “V.” The safety tube is in register with the needle, and the fin of the needle is out of the rectangular hole. During infusion, the fin is pushed to make the needle slide along the slit out of the tube, and after infusion, the needle slides back into the tube for safety. The safety tube has been commissioned to a qualified manufacturer and applied to the clinical trial. Meanwhile, it was approved by the hospital ethics committee.