Can exposure to rain on a hot day increase the risk of contracting a viral illness?

From the Guidelines

Playing in the rain on a hot day will not directly cause viral illnesses, as viruses are not created by rain or temperature changes, but it may increase the risk of transmission if you are exposed to contaminated droplets or surfaces. Getting wet and cold may temporarily lower your body's defenses by causing stress on your immune system, but you need exposure to a virus to actually develop a viral infection 1. The old belief that "getting wet causes colds" is a misconception - you can only catch a virus by being exposed to it through contact with an infected person or contaminated surfaces, such as those contaminated with rhinovirus, human coronavirus, respiratory syncytial virus (RSV), and adenoviruses, which are responsible for common colds 1. That said, crowding indoors during rainy weather can increase virus transmission between people, as seen with measles, which can be spread through droplet transmission from the nose, throat, and mouth of infected persons if they cough or sneeze 1. If you enjoy playing in the rain, there's no need to worry about automatically getting sick, but it's still wise to dry off afterward, change into warm clothes, and wash your hands to maintain good overall health, as Streptococcus pneumoniae bacteria can spread through contact with an infected person or contaminated surfaces 1. The temporary physical stress from being cold and wet might make you more susceptible if you're already exposed to viruses, but the rain itself doesn't contain or create viral pathogens.

Some key points to consider:

• Viruses such as measles, influenza, and common cold viruses can be spread through droplet transmission or contact with contaminated surfaces 1.
• Crowding indoors during rainy weather can increase the risk of virus transmission between people 1.
• Good hygiene practices, such as washing your hands and drying off after being in the rain, can help reduce the risk of transmission 1.
• Certain groups, such as children, the elderly, and people with weakened immune systems, may be more susceptible to infections such as Streptococcus pneumoniae 1.

It's essential to prioritize good hygiene practices and take steps to reduce the risk of transmission, especially during rainy weather when people may be more likely to crowd indoors. By taking these precautions, you can enjoy playing in the rain while minimizing your risk of getting sick.

From the Research

Viral Diseases and Rain Exposure

• There is no direct evidence to suggest that playing in the rain on a hot day can get you sick with a viral disease.
• However, viral diseases such as the common cold, sore throat, and sinusitis are caused by viruses, and some are caused by bacteria 2.
• Influenza is an acute viral respiratory infection that causes significant morbidity and mortality worldwide, and it is highly contagious 3.

Fever Response and Viral Infections

• The effect of acetaminophen on fever in bacterial vs. viral infections was tested, and there was no significant difference in the fever response to acetaminophen between the two groups 4.
• Fever may have a benefit in shortening the duration of viral illness, and the antipyretic efficacy of ibuprofen may be hindering the benefits of a fever response when taken during the early stages of COVID-19 illness 5.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for the management of fever, pain, and inflammation, but they have always been considered to have a double-faced role, according to their capacity to manage inflammation but also their possible reduction of immune system response and diagnosis delay 6.

Management of Viral Symptoms

• Annual influenza vaccination is recommended for all people six months and older who do not have contraindications 3.
• The use of ibuprofen to treat fever in COVID-19 may have a possible indirect association with worse outcome, and it is plausible to hypothesize that the antipyretic efficacy of ibuprofen may be hindering the benefits of a fever response when taken during the early stages of COVID-19 illness 5.
• The NSAID may be chosen considering the characteristics of the patient, the comorbidity, and the polytherapy 6.