Age and Job Affect Likelihood of Spreading Infectious Disease

Although it is common sense that some jobs may be associated with more social contacts, the survey is believed to be the largest national study of its kind to date and allowed the scientists, for the first time, to quantify social contact patterns and how these varied with age and job.

A social contact was defined as a face-to-face conversation within 6 feet or skin-on-skin physical touch with another person. According to the study, children had the highest number of social contacts, making them most at-risk for catching and transmitting infection.

Among adults, those working in schools, in the health sector and in client-facing service jobs such as retail positions had among the highest number of social contacts. Students, unemployed people and retired people had among the lowest levels of social contacts.

According to the data collected, during a working day a teacher sees on average 62.1 different people, whereas a retired person only sees around 19.3 The length of time a person spends with a contact is an important risk factor in transmitting infection, so the results were converted into total contact hours, the sum of the durations of all contacts in one given day.

Most people have an average of around 26 social contact hours a day, but a small number have up to 50 contact hours a day since people can spend time with more than one individual simultaneously.

Dr Leon Danon from the Mathematics Institute at the University of Warwick said, “People working as teachers or health professionals are no doubt already aware that they have higher risks of picking up bugs like colds and flu. But before this study there was very little data mapping out the contact patterns humans have in their daily life. By quantifying those social interactions, we can better predict the risks of contracting and spreading infections and ultimately better target epidemic control measures in the case of pandemic flu, for example.”


Social group

(average) Social contact hours

Number of respondents




Transport workers






Service sector workers



Health sector workers



Teaching staff






Office workers



Home-based workers






Research staff













Source: University of Warwick

Something in the Air

“That filtering mechanism, just like the filters in your house, can be overwhelmed to where they don’t work anymore,” said Dr. Jason Sigmon, “And then you’re going to be directly challenged by those things in the environment. Those are the things that we see with patients who typically don’t have lung problems.”

Wearing a mask in areas of heavy debris can be very effective at preventing tornado cough. For public health officials in Oklahoma, their capability to track the number of patients reporting tornado cough symptoms will determine their ability to mitigate such issues in the future.

In related news, a recent article in Popular Science revealed that scientists have discovered billions of bacteria thriving in Earth’s upper atmosphere. The scientists collected samples from the air 33,000 feet above the earth’s surface and discovered that  20 percent of what they had assumed to be just dust or other particles was actually alive.

The researchers found E. coli in the samples, which they believe hurricanes lifted from cities. They plan to investigate whether the bacteria could be making its way into rain water. This news is especially revelatory in light of the SARS-like spread of MERS coronavirus.

New Study: Universal Paid Sick Leave Reduces Spread of Flu

The researchers simulated an influenza epidemic in Pittsburgh and surrounding Allegheny County. The results of the study are reported in the American Journal of Public Health.

“The Centers for Disease Control and Prevention recommends that people with flu stay home for 24 hours after their fever breaks,” said lead author Supriya Kumar, Ph.D., M.P.H., a post-doctoral associate in Pitt Public Health’s Department of Epidemiology. “However, not everyone is able to follow these guidelines. Many more workers in small workplaces than in large ones lack access to paid sick days and hence find it difficult to stay home when ill. Our simulations show that allowing all workers access to paid sick days would reduce illness because fewer workers get the flu over the course of the season if employees are able to stay home and keep the virus from being transmitted to their co-workers.”

For public health officials, this means that informing communities about the importance of sick days during flu season could have a large impact on reducing overall healthcare costs by minimizing workplace influenza transmission.

In addition to investigating the impact of universal access to paid sick days, Dr. Kumar and her colleagues looked at an alternative intervention they termed “flu days,” in which all employees had access to one or two paid days to stay home from work and recover from the flu. The idea behind flu days is that they encourage employees to stay home longer than they currently do, thus reducing the potential for them to transmit illness to colleagues at work.

Giving employees one flu day resulted in more than a 25 percent decrease in influenza infections due to workplace transmission. A two flu-day policy resulted in a nearly 40 percent decrease. The researchers found that universal access to paid sick days was more effective for smaller companies, whereas the “flu days” were more effective for larger workplaces (defined as having 500 or more employees).

“These findings make a strong case for paid sick days,” said Dr. Kumar. “Future research should examine the economic impacts of paid sick-day policies.”

31st MERS Coronavirus Fatality Reported in Saudi Arabia

The WHO has also reported laboratory-confirmed cases of MERS-CoV originating in Jordan, Qatar, Saudi Arabia, and the United Arab Emirates.

The virus has appeared in France, Germany, Italy, Tunisia, and the United Kingdom as well, but the patients were either transferred there for care, or returned from the Middle East and subsequently became ill. In France, Italy, Tunisia and the United Kingdom, there has been limited local transmission among patients who have not been to the Middle East but have been in close contact with laboratory-confirmed or probable cases.

A clinical study published in The Lancet last week suggests that MERS-CoV might have a longer incubation period than previously thought, which would mean that longer quarantine periods may be required to rule out infection among patient contacts.

Based on the current situation and available information, the WHO encourages all Member States to continue their surveillance for severe acute respiratory infections and to carefully review any unusual patterns.