10:11 AM

399 - Delayed Antibiotic Prescription, Sunscreen 2021, UPF Clothing

Take 3 – Practical Practice Pointers©

From the Literature

1)  Delayed Antibiotic Prescribing for Respiratory Infections

The problem of antibiotic over-prescribing for upper respiratory infections (URI) is well-documented. The threat of antibiotic resistance, unnecessary complications for antibiotic use and added cost to the system are three important reasons we would want to decrease the rate of over-prescribing. Delayed antibiotic prescribing (also known as a “wait and see prescription” or “pocket prescription”) is one strategy to counter this problem. Previous systematic reviews have favored these generally but have been criticized because of the heterogeneity of the included studies and the lack of ability to dig into the specific patient data to understand any subgroup effects. The authors of a new systematic review have completed an “individual patient data” meta-analysis (IPDMA) to address these issues. IPDMAs combine the original datasets from previous studies (not just published results) and allow more detailed analysis than traditional meta-analysis.

The authors searched for and selected ambulatory RCTs and observational cohort studies that addressed respiratory infections (all URIs as well as “lower respiratory infection and/or cough”) across adult and pediatric populations with either a delayed, immediate, or no antibiotic prescription. The outcomes included symptom diaries, patient satisfaction, admissions, and complications.

Out of 22 eligible studies located, the researchers could only get individual patient data from 9 RCTs and 4 observational studies which described outcomes for over 55 thousand subjects. Most were conducted in primary care from Western, developed countries and spanned all ages and multiple types of respiratory infection. The studies were generally at low-moderate risk of bias, particularly blinding and selection bias.

Meta-analysis of the primary outcome – symptom severity at 2-4 days – showed no significant overall differences between delayed, immediate and no antibiotics. Children less than 5 years had slightly less severe symptoms at 2-4 days with immediate antibiotics. Symptoms lasted a bit longer with delayed vs. immediate antibiotics (11.4 days vs.10.9 days), but complications were no different. Patient satisfaction was slightly better with delayed vs. no antibiotics. Heterogeneity, which had plagued the previous reviews of published aggregate data, was not a significant factor using the individual patient data.

John’s Comments:

This study did not address ultimate antibiotic usage among patients, which, in other studies is usually decreased. It does provide reassurance that delayed antibiotics are a productive and safe alternative to a binary antibiotics/no antibiotics decision.


  • Stuart B et al. Delayed antibiotic prescribing for respiratory tract infections: individual patient data meta-analysis. BMJ. 2021 Apr 28;n808. Link


In Preparation for the Summer

2)  Sunscreen 2021: Let the Wearer Beware

According to the American Academy of Dermatology (AAD), it is estimated that one in five Americans will develop skin cancer in their lifetime. Sun protection is the most effective way to prevent skin cancer. The sun protection factor (SPF) is a relative measure of how long a sunscreen will protect from UVB rays, which are the chief cause of sunburn and a contributor to skin cancer. Usually the number is explained as the amount of time it takes an individual’s skin to burn when it’s covered in sunscreen compared with when it’s not. For example, assuming you apply—and reapply—the sunscreen correctly, if you’d normally burn after 20 minutes in the sun an SPF 30 protects for about 10 hours.

SPF calculations do not apply to UVA rays, which can tan and age skin, and also trigger skin cancer. That’s why it is necessary to use a broad-spectrum sunscreen that provides protection against both types of UV rays. However, no sunscreen blocks 100 percent of UVA or UVB rays. The breakdown: SPF 30 blocks 97 percent of UVB rays, SPF 50 blocks 98 percent, and SPF 100 blocks 99 percent. The AAD recommends everyone use water resistant sunscreen that offers broad-spectrum protection against UVA and UVB rays at a SPF 30 or higher.

Application of the product is vitally important. The AAD notes:

  • Most people only apply 25-50 percent of the recommended amount of sunscreen.
  • Sunscreen should be applied to all skin that clothing will not cover. Most adults need about 1 ounce — or enough to fill a shot glass — to fully cover their body.
  • Protection for the tops of feet, neck, ears, and top of head is often neglected
  • Sunscreen should be applied to dry skin 15 minutes before going outdoors
  • To protect lips, apply a lip balm/lipstick with an SPF of 30 or higher.
  • When outdoors, sunscreen should be reapplied approximately every two hours, or after swimming or sweating, according to the directions on the bottle.

It is also important to note that sun protection may be required indoors if much time is spent sitting near a sunny window. Glass blocks UVB rays, but it can let through some of the UVA rays that are primarily responsible for wrinkles and skin cancer.

Surprisingly, the 2020 CARES Act included new sun-care guidance. The sun care industry had been awaiting the FDA’s updated proposed requirements for sunscreens, which were to be issued in late 2019 via a new over-the-counter (OTC) sunscreen monograph system (sunscreen rulebook), but which never happened. This will now reportedly happen in September 2021. The CURES Act;

  • deemed the current U.S. chemical filters safe until further notice
  • allowed marketing for SPF 100-plus formulas
  • laid the groundwork for American companies—many with an existing presence in other markets—to work with international chemical manufacturers to begin the process of introducing new sunscreen actives to the US

The Consumer Reports company has recently published its 2021 sunscreen ratings. In the past few years, the company has consistently noted that many tested products perform at less than half their labeled SPF number and many are inconsistent in their protection across product batches. Since the AAD recommends using a product with an SPF of 30 or higher, this means that many cases, users are not adequately protected, even with listed SPF ratings of 50. This also means that most products with an SPF rating of 30 are not sufficient.

Additionally, testing has consistently found that so-called natural or mineral sunscreens (those that contain only titanium dioxide, zinc oxide, or both as active ingredients) have tended to perform less well. This does not include products labeled sunblock, such as higher concentration zinc oxide products (think white noses on lifeguards).

Top Rated Products:

  • Lotion: Equate (Walmart) Sport Lotion SPF 50
  • Spray: Hawaiian Tropic Island Sport SPF 30

My Comment:

The FDA requires sunscreen makers to test their products but does not necessarily require them to submit their results. What makes this report compelling is that the same evaluation process was used on all products under the same conditions (less potential bias than a company testing their own product). It is vital to note that the SPF is for UVB rays, NOT UVA rays. This should be a concern for all who depend on sunscreen as their primary sun protection. There is also ongoing concern as to how much some of the presently commonly used active ingredients are absorbed, and the recent CURES Act really did nothing to resolve this. Note that the Consumer Reports testing has consistently found that cost and “brand name” are not necessarily “better” and there can be incredible variation in quality/consistency even among the various products from the same manufacturer.


  • Consumer Reports Suncreeen Ratings: April 2021 (full report only available to

subscribers). Ratings

  • American Academy of Dermatology Sunscreen FAQs: Link

Question From a Colleague

3)  The Effectiveness of UPF Clothing for Sun Protection

Question: With the imminent arrival of summer, I’m wondering about the effectiveness of “SPF Clothing. And is it worth the cost?”

Answer: There is actually no such thing as SPF clothing. Clothing/fabrics are tested using a UPF (Ultraviolet Protection Factor) rating system. The UPF rating indicates how much UV radiation (UV-R) will pass through the fabric; the higher the rating the greater the protection. A UPF 25 means 1/25 (4%) of UV-R will pass. UPF 50 means 1/50 (2%) will be able to penetrate the fabrics. The highest UPF protective level is 50+, which means less than 2% of the UV-R may be penetrating the clothes. There is no “official” UPF higher than 50+. In general, UPF clothing loses protection when wet.

Currently, manufacturers follow voluntary testing guidelines and use private labs to determine a fabric’s UPF rating. The most common standard used in the US to “rate” UPF clothing is ASTM (formerly the American Society for Testing and Materials). Some manufacturers also use the AS/NZS (Australia/New Zealand Standard). They are similar in terms of the measurement process used. In general, advanced textiles and fabrics score better for UPF ratings. Polyester & Nylon are best for UV reflection. Wool and silk are moderately effective. Cotton, rayon, flax and hemp are the least effective.

The Federal Trade Commission monitors UPF advertising claims. If a manufacturer adds a tag with a UPF 15-50+ rating to any product, it must adhere to the testing standards outlined above. No clothing item with an Ultraviolet Protection of less than 15 can be labeled “sun-protective”.

Interestingly, Consumer Reports did a study in 2015 comparing the UPF of three white shirts, only one of which had a UPF claim. The UPF 50+ rated rash guard, which was a blend of 84 percent polyester and 16 percent spandex embedded with titanium dioxide, delivered a UPF of 174. A cotton long-sleeve T-shirt which was thicker than a regular T-shirt had a UPF of 115 and an non-rated long-sleeve compression crew made of the same polyester/spandex blend as the UPF 50+ rash guard had a UPF of 392. When wet, the 50+ UPF shirt’s UPF actually increased to 211, the blend decreased to 304, and the cotton T-shirt decreased to a UPF of 39.

The American Academy of Dermatology emphasizes the importance of sunglasses with UV protection for eye protection, noting that lenses that appear dark do not necessarily offer UV protection. In addition, large-framed or wraparound sunglasses offer more sun protection than aviators. The AAD also notes that a wide-brimmed hat is an effective way to cover up face and neck, and that baseball hats or straw hats with holes should be avoided as they are not as effective in providing face, ear, and neck protection.

My Comment:

Clothing can offer excellent sun protection without having a UPF label. For example, it is estimated that jeans have a UPF of approximately 1700! However, a normal thickness white t-shirt has a UPF of 5. While there is usually a cost differential between regular shirts and UPF-labeled products, when one considers that the average sunscreen costs somewhere between $6-12, a sunshirt that will last years (and that you don’t have to worry about “reapplying” after 2 hours, after swimming, or after sweating) begins to look like a good bargain indeed. Note that the most popular “sun hat,” the baseball cap, protects the head and forehead well, but not much else.


  • American Academy of Dermatology: What to wear to protect your skin from the sun: Link Infographic: Link
  • Consumer Reports Sun Protection Clothing: Report


Mark and John

Carilion Clinic Department of Family and Community Medicine

Feel free to forward Take 3 to your colleagues. Glad to add them to the distribution list.

Email: mhgreenawald@carilionclinic.org