Behaviors National changes

Flu and COVID19 and Fall

There are two hypotheses regarding what will happen this Fall: 1) flu season will be, essentially, non-existent because people are wearing masks and social distancing (due to COVID19); or 2) the combination of flu and COVID19 epidemics will add strains to the healthcare system that we’ve never seen before.

The US is lucky though because flu seasons hits the Southern Hemisphere before hitting us. Their flu seasons is from June to September (peaking in August). Every year, we use this to our advantage to predict our flu season.

So, now that their flu season is over, what did it look like in the Southern Hemisphere (and specifically Australia, Chile, and South Africa)?

  • VERY little flu activity. In 2020, Australia, Chile and South Africa had 0.06% positive flu tests (51 out of 83,307). For a comparison, from 2017-2019, they had 13.7% positive flu tests (24,512 out of 178,690).

We are seeing similar trends during the non-flu season in the U.S.…

  • Typically, during the non-season we have about 1-2% of positive flu tests. This year we have 0.2% positive flu tests.

So, it LOOKS like hypothesis #1 is what we can expect this Fall. Thanks to the community mitigation measures to reduce COVID19, we will also reduce flu transmission. We have to keep it up though (and go get your flu shots!) or hypothesis #2 will take over.

Love, YLE

Data Source: Olsen SJ, Azziz-Baumgartner E, Budd AP, et al. Decreased Influenza Activity During the COVID-19 Pandemic — United States, Australia, Chile, and South Africa, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1305–1309. DOI: icon

Behaviors National changes

Need another reason to wear a mask?

We already know a few things…

  • If you wear a mask, you’re protecting those around you (whether you know it or not). A mask reduces the distance and the number of droplets when talking, sneezing, or coughing. With 40% of cases being asymptomatic, universal mask wearing is especially important because you may be spreading the disease even if you feel great
  • A mask can protect the wearer by blocking particles from coming into the nose and mouth. For example, after universal mask wearing was implemented in Boston hospitals, infections decreased among health care workers.

The New England Journal of Medicine recently published another possible reason to wear a mask. This is NOT peer-reviewed science, it is an educated guess (hypothesis). Meaning the scientists used previous studies to make this guess. However, for the TOP medical journal (and I mean TOP) to publish a hypothesis means there is legitimate weight behind this guess.

What are they guessing? Universal mask wearing reduces the severity of COVID19 among those who do wear a mask.

Why? In epi, there is this concept called “dose-response”. For COVID19, this means the more virus particles you are exposed to, the more severe your symptoms/outcomes will be. And vice versa. So, if someone sneezes directly on your face you will get much sicker than touching COVID19 on a surface.

SOO, their thought process is that if you wear a mask, you filter out a lot of virus particles (dependent on mask type), and then your disease/symptoms will be less severe. In fact, this allows more people to get the asymptomatic disease MORE (compared to symptomatic disease). This is good because even among asymptomatic and mild cases of COVID19 you can develop antibodies. We get closer to herd immunity.

We have seen this, anecdotally, in a few instances:

  • Argentinian cruise ship, where people were provided masks, asymptomatic infection was 81% (compared to 20% in earlier cruise ship investigations)
  • US food processing plants, people were provided with masks each day, 95% were asymptomatic and 5% experienced mild-to-moderate symptoms during recent outbreaks
  • Countries with population-wide masking have fared beer in terms of COVID19 rates and deaths
  • Syrian hamster models (i.e. not humans) this hypothesis has shown to work

This is an educated guess. Now, other epidemiologists will (hopefully) test this guess to see if it is true. IF this is hypothesis is true, it’s a game changer, especially in the US while we wait for a vaccine with less-than-ideal testing and response.

Love, YLE

Data sources:

This guess:

Masks work:;;

Hamster study:

National changes

Vietnam: COVID19 Success Story

Home to 100 million people, Vietnam’s first case arrived from China on January 23. Since, they’ve had a TOTAL of 1,059 cases and 35 deaths. Also, 93% of Vietnamese people believed the government responded very well.

So, what did they do? They had a bit different approach than the United States (and S. Korea and New Zealand, see previous posts). Their response can be categorized into 5 buckets:

Investment in public health BEFORE the pandemic

  • Vietnam has invested an average rate of 9% per year into public health since 2000. This resulted in an increased life expectancy, decreased infant mortality, 97% immunization rate, and an extremely low obesity rate.
  • After SARS (even though they were the first country to be declared SARS free), they invested even more including the development of a national public health emergency system, including a hospital reporting network.

Early action

  • BEFORE cases were even identified in the country, Vietnam limited mobility within the country and implemented closures.
  • 1 week after the first case, travel to and from China was closed
  • 1 week after the first case schools were closed
  • 12 days after the first case, trains were stopped

Contact tracing and testing

  • A uniquely comprehensive contact tracing program included not only identifying an index case, but identifying everyone up to 5 degrees removed from the index case.
  • 2 weeks from the first case, Vietnam developed their first diagnostic COVID19 testing kit
  • When an index case was identified, there was widespread local testing. No cases were missed.


  • Vietnam not only quarantined based on symptoms, but also by epidemiological risk of infection. Because there is about 40% of the population without symptoms, this likely attributed a LOT to their success.
  • Like New Zealand, Vietnam provided quarantine facilities to over 200,000 people

Clear communication. To me, this was the most interesting aspect of Vietnam’s response.

  • Before there was 1 case in Vietnam, the Ministry of Health warned citizens of the serious threat. This set the scene.
  • In February, the national Health Department released a pop song called “Ghen Co Vy” meaning “Jealous Coronavirus” and turned it into a handwashing public service announcement. Here is the wonderful 3 min campaign:
  • The health department also used social media and text messages for clear and concise messages like “Fighting the epidemic is like fighting against the enemy”

Absolutely incredible. Get it Vietnam!!

Love, YLE

For more detail on the response:

Here is the previous post on the New Zealand success story:

And here is the previous post on South Korea success story:

Long-term effects National changes

Research Opportunity

Please consider taking part in this anonymous survey!

My brilliant colleagues, Dr. Meliha Salahuddin and Dr. Divya Patel, at the University of Texas Health Science Center at Tyler are collaborating with the University of Texas Rio Grande Valley School of Medicine to conduct a study on the impact of COVID-19 on your daily life, health and well-being.

If you live in the US and are 18 years or older, please click the link below to get started. It is completely voluntary, anonymous, and takes about 15-20 minutes to complete (I think it took me more like 20-25 minutes).

English version:; Spanish version:

Please feel free to circulate this post or the survey links through your work, community-based and social networks. A direct link to study website can be found at

Love, YLE

Behaviors National changes Social Distancing

Protective measures in the US

While quite a bit of research has reported which COVID19 policies work and don’t work on a country or state-level, VERY little peer-reviewed research has reported what individuals are doing to curb spread. In other words, are individuals conforming with the recommended protective health measures?

A study was just published in the International Journal of Environmental Research and Public Health.

Scientists used data from the COVID19 Impact Survey. This survey was designed carefully to pick a random set of households in the US to participate. They did this extra work so the results of the study could be generalized to the entire U.S. (instead of just one state/city or type of state/city). This survey was done three consecutive times (April, May, and June of 2020) and 25,269 people participated.

What did they find?

  • In the United States, 95% wash their hands, 90% kept 6 feet away, 86% wore a mask, and 82% avoided crowded places (Figure 1)
  • Of 19 protective measures, an average of 7 protective measures were taken
  • Who took protective measures more? Higher incomes, insurance, higher education levels, large household size, age 60+, females, minorities, those who have asthma, have hypertension, overweight or obese, and those who suffer from mental health issues during the pandemic
  • Who took protective measures less? Suburban and rural areas, and the Midwest and West
  • People who wore masks increased from April to June 2020 (Figure 2)
  • Participants who were positive for COVID19, knew an individual with COVID19, or knew someone who died from COVID19 had a stricter lifestyle. This was especially true regarding washing hands, avoiding public places, and canceling social events.
  • Some protective measures are linked to others (Figure 3)

Now, what people say they do may be different from what they actually do. However, this still makes my little epidemiologist heart happy. People know the social desirability of our community, which lines up with effective protective measures. Also, this data uncovers patterns that would otherwise have been obscured. Epidemiologists can leverage this knowledge to more quickly and effectively curb COVID19 spread.

I’m hoping that COVID19 Impact Survey’s hard work continues because I would love to see numbers for July-September too.

Love, YLE


COVID19 Impact Survey:

Behaviors National changes

BLM protests vs. Sturgis Motorcycle Rally

Why was the COVID19 spread so different for these two events? A valid question to follow-up the Sturgis post yesterday.

I (and other public health officials) hypothesized that BLM protests would exacerbate COVID19. Protesters reduced social distancing behavior, were shouting and yelling (i.e. spreading droplets), and congregated in large groups. This could have spurred a resurgence. However, as more and more data comes in, this does not seem to be the case.

One white paper, published by 5 scientists, looked closely at BLM protests in 315 of the largest US cities from May 15-June 9.

Their purpose? To see if the BLM urban protests impacted social distancing in communities, COVID19 cases, and COVID19 related deaths.

What did they find? • Stay-at-home behavior increased across these cities during the protests. The authors attribute this to fear of danger, avoiding travel outside the home due to additional traffic congestion or street closures, or due to lack of available activities from businesses closures near protest sites. • There is no evidence that protests sparked COVID19 case or death growth 5 weeks following the onset of protests

Why was our hypothesis wrong? • I didn’t think about non-participants’ behaviors when I made the initial hypothesis. More people, who were not protesters, stayed inside. This is consistent with the literature on crime, violence, and perceived safety amongst the general population.

So why was BLM different than Sturgis? • The sheer amount of people in one place. Both had about 500,000 people attend, but BLM was spread over 500 cities while Sturgis was in 1 city. The high density at 1 event makes it far more difficult to social distance. • Difference in spaces (Sturgis also took place in bars, tattoo parlors, hotel rooms, etc.) • Difference in testing behaviors. I can only speak for Texas, but we offered free COVID19 testing for protesters. We are hearing anecdotally, from contact tracers in the area, that bikers are either not interested in getting tested or refuse to admit they went to the rally if they are tested • Other hypotheses? Differences in face mask use, ages of attendees, and travel to and from the sites (protesters did travel to BLM events, however this was not 100% like Sturgis).

Why is this comparison important? It contributes to the current discussion around policies for controlling the spread of disease. Especially when it comes to large events. Because we ALL want to get make to normal one day.

Love, YLE


National changes Predictions

COVID19 Deaths and the recent 6% debacle

There have been rumors, and tweets, and screenshots, and who knows what else stating that only 6% of CDC’s COVID19 death count is due to COVID19. I feel like this is a ridiculous post, particularly because I feel like a broken record, but here we go…

What happened? CDC updated its regular statistics page stating: “For 6% of the deaths, COVID-19 was the only cause mentioned.” For the other 94% of people that died of COVID19, “individuals had an average of 2.6 additional conditions or causes per death”.

What does this change? NOTHING. 182,885 people have still died from COVID19 in the US. COVID19 is still the third leading cause of death in the US.

What does the science say?

1. The CDC (and basically every scientist across the world) has consistently stated that individuals with underlying health conditions are more likely to die from COVID19. This is probably one of the first facts that we DID know. I don’t know why we are surprised about this now…

2. Long-term conditions (like obesity, diabetes, or heart disease) are “chronic” because they last for a long time. Most are, in fact, manageable thanks to modern science. Someone with diabetes (that wasn’t “supposed” to die this year) can manage to get infected with COVID19 and die quickly because their immune systems get overwhelmed.

3. The health of our nation has been terrible, even before the pandemic. 60% of adults have a chronic condition. Among those aged 65 and over, 80% have multiple chronic conditions. Minorities and low-income populations have more chronic conditions too. So, if you take a random sample of people who die, the majority will have at least one chronic condition. So we shouldn’t be surprised about this 6% being low.

4. There are many lines on a death certificate. This includes the “immediate cause of death”, “sequentially conditions leading to the cause of death”, and “other significant conditions contributing to death”. Which ties to #3…it would be odd if a chronic condition WASN’T listed on a death certificate in the US given the health of our nation overall and given COVID19 touches every organ system. Death certificate instructions are below if you’re curious how this data is collected.

5. If there is nothing else, just look at an excess death graph for 2020 (see Figure). We are WAY above our deaths this year compared to past years. Period. This doesn’t just randomly coincide with a pandemic.

In epidemiology (and science), it’s very weird for us to beat a dead horse. We typically accept the conclusions of a room full of scientists with decades of experience until another room of scientists with decades of experience proves them wrong. We don’t change our mind from a tweet that is taken out of context (no matter who it’s from). The public should follow suit. I guess I should just be happy that everyone (and I mean everyone) now pays attention to public health?

Love, YLE

CDC link to deaths causing the commotion: conditions and of COVID19 death: ; Chronic conditions, overall, in the US:; certificate instructions: Excess Deaths posts:; COVID19 as a leading cause of death: Image from: Weinberger lab, updated on August 14, 2020

Antibodies Children GA Innovative Solutions National changes Social Distancing


Buckle up. In true 2020 fashion, several scientific developments popped up while I was on vacation…

1. Teachers’ and parents’ risk for severe COVID19

• 2.95 million teachers (50.6%) have risk factors for severe COVID19. This is mostly driven by obesity or heart conditions

• 37.7 million adults living with school-aged children (54%) have risk factors for severe COVID19. This is mostly driven by age, heart problems, or diabetes

• Risk is the same for those living with younger children compared to older children.

• So… what? “Without adequate safeguards, reopening schools could put millions of vulnerable adults at risk for severe COVID-19 illness”.

2. First global case of COVID19 re-infection

• In March, a 33-year-old man in Hong Kong was infected with COVID19. He had mild symptoms.

• Last week, he was infected with a different COVID19 strain and tested positive upon his arrival to Hong Kong from Spain. He is asymptomatic.


• After the first infection, he had no antibodies. But we already know that not everyone gets antibodies (especially mild symptoms; see my previous posts)

• After the second infection, he did produce antibodies. This is consistent with the immune system building stronger with each exposure to a pathogen, so second and third exposures may increase the chances to develop antibodies.

• In the words of immunologist Dr. Akiko Iwasaki, “This is no cause for alarm – this is a textbook example of how immunity should work.”

• Vaccination (and social distancing and masking) needs to be considered among people that have already been infected with COVID19

3. Wearing masks works (I feel like this is no duh, but in case you needed more ammunition)

• US states with high mask wearing compliance were more likely to have a R(t) less than 1 (control of community transmission)

• Mask wearing was higher among women, elderly, non-white or Hispanic, lower income people

• Mask wearing is highest along the coasts, southern border, and urban areas (see Figure)

• Mask wearing is even more important when (or if) social distancing is relaxed

4. Super-spreaders played a key role in MERS and Ebola. Their role in COVID19 was just revealed in Georgia:

• 2% of the population is responsible for 20% of infections• Super-spreaders likely explain major outbreaks in rural areas • Younger people are more likely to be super-spreaders

Love, YLE





California Deaths National changes Testing

Early Spread of COVID19

Many tested negative for the flu in January and February. Could this have been COVID19?

Short answer: Yes.
Long answer…

We have to outline the first “original” cases:

• Jan 21-Feb 23: U.S. detected 14 COVID19 cases all related to travel from China

• Feb 26: 1st non-travel US case confirmed in CA (patient was ill starting Feb 13)

• Feb 28: 2nd non-travel US case popped up in WA

So, from this timeline, COVID19 started spreading in the United States on Feb 26 right? Nope.

CDC found that it was spreading earlier in the US by looking at four things:

1. Seattle Flu Study: Some scientists, during this time, just happened to be conducting a Seattle Flu Study. They were basically monitoring the flu from Nov 2018- March 2020 by testing people randomly. After the pandemic started, they went back to test these samples for COVID19. From Jan 1-Feb 20, none of their tests were positive. Their first sample was positive on Feb 21; the following week there were 8 positives; the following week there were 29 positives.

2. Gene analyses: Genes from early cases suggest that a virus imported directly or indirectly from China began circulating in the US between January 18 and February 9, followed by a COVID19 strain from Europe.

3. CDC has found other cases before Feb 26

• Jan 31: CA women became ill. Died 6 days later. She did not travel internationally. Postmortem, COVID19 positive.

• Feb 11: An infected passenger boarded the Grand Princess in Seattle leading to two outbreaks.

• Feb 13: CA man died at home. He did not travel internationally. Postmortem, COVID19 positive

4. Surveillance: ER records did NOT show an increase in visits for COVID19–like illness until February 28. CDC thinks this is because there were too few people with the disease to see an increase in ER visits in a meaningful way.

Translation? Community spread of the Chinese COVID19 strain likely started in January. Community spread of the European COVID19 strain started in Feb.

Why do we care? There are many reasons. One being that we can better estimate how many people truly died from COVID19 that were missed. We know from excess death analyses that we missed a lot in the beginning, meaning our current numbers are underreporting.

Love, your local epidemiologist

Data Source: Jorden MA, Rudman SL, et al. Evidence for Limited Early Spread of COVID-19 Within the United States, January–February 2020. MMWR Morb Mortal Wkly Rep 2020;69:680–684. DOI: icon

National changes

S. Korea: Another COVID19 success story

S. Korea flattened their curve QUICKLY. Since Jan 20, they’ve had 14,714 cases (28 cases per 100,000) and 305 deaths (6 per 1 million).

This success was due to their flawed 2015 MERS response. After MERS, they made several changes to their health system, insurance system, and strengthened relationships between public and private agencies. This foundation allowed them to respond quickly to COVID19.

S. Korea had a much different approach to New Zealand (see previous post). S. Korea didn’t close businesses, didn’t issue stay at home orders, and didn’t close their borders. They focused on three other proactive public health interventions within DAYS of their first case:

1. Testing and Screening. Opened 600 testing centers with the capacity to reach 15,000-20,000 per day (39 per 100,000). Screened for COVID19 at the front doors of businesses.

2. Treatment. Recruited 2,400 health professionals to the large urban areas. Increased hospital capacity quickly by building temporary hospitals.

3. Containment. Isolated cases and contact traced. The most comprehensive contact tracing program in the world through the development of an IT system aggregating a wide range of both medical and nonmedical data.

Image from JAMA. See full reference below.

While this has been a great public health success, the unusual thoroughness of their contact tracing has been questioned. Three S. Korea law professors described this in a JAMA article.

Briefly, once someone was COVID19 positive, their deidentified information (sex, nationality, age) was made public. However, some regional governments went further to provide information on the infected person’s route, including the name of the restaurants, shops, and other businesses. This allowed for the unveiling of cases, embarrassing personal details, and public distain (sometimes even in the media).

S. Korea’s National Human Rights Commission called to limit governments’ ability to publish this information. They were successful on March 9 for future COVID19 cases.

Nonetheless, the authors concluded “It is critical to balance the need for information to test, track, and quarantine with legitimate privacy concerns….Further refinements are needed to better protect the privacy of infected individuals while not sacrificing the effectiveness of the measures taken”.

Love, your local epidemiologist

PS There are some great testimonials from S. Koreans within the comments on the Facebook post

Source: Data from Johns Hopkins, first figure by me.

JAMA article