Thread by @Daniel_E_Park

How our family stayed COVID-negative when my 2-year old was infected. An epidemiologists’ perspective.

In late February, our toddler woke up with a runny nose. Anyone with a toddler will know runny noses are very typical. However, thanks to ongoing local surveillance (which I monitor ~weekly), I knew case rates were slightly elevated in our area, and that led me to test.

Lesson 1: If you know local circulation rates, you can adjust your threshold for when mild symptoms may warrant a test.
Lesson 2: We can get tests for free from our local library. This is a great resource that should remain widely available.

His first test came back with a very faint positive line. So faint, in fact, that I gave him another rapid test. Clear negative. Third was also a clear negative. Fourth (by which he was starting to get annoyed with me) finally confirmed the faint positive.

Lesson 3: Not all rapid tests are created equal. And sometimes those positives are truly faint. When in doubt, try another test. PCR is most sensitive but not as readily available. A positive rapid antigen means you are likely infected and infectious.

We were fortunate to catch this fairly early when he was slightly less infectious. Since he had primary COVID vaccination, which accelerates clearance and lowers viral load, I knew we’d have to “lock it down” for ~4-5 days to minimize transmission risk.

Lesson 4: Staying up to date with vaccines decreases transmission risk and shortens time to clearance when infected. I was also less worried about his well-being as vaccines reduce risk of long COVID and severe symptoms.
ncbi.nlm.nih.gov/pmc/articles/P…

Risk Mitigation Strategy 1a: First thing we did was to open some windows. Improved ventilation is critical in reducing the amount of potentially aerosolized virus. We also had a small HEPA filter I placed outside his bedroom and left running.
ncbi.nlm.nih.gov/pmc/articles/P…

Strategy 1b: Anytime he went to the bathroom (#2), we would turn on the exhaust. We would also close the lid and leave the bathroom immediately after flushing. Toilet flushes aerosolize viral particles.
ajicjournal.org/article/S0196-…

Lesson 5: Increasing air circulation and filtration is critical in enclosed indoor environments, including bathrooms.

Strategy 2: Masks. My wife and I used high filtration masks, particularly during days 2-5 when he was coughing and more readily positive on his rapid antigen text. Both kids would also mask, especially when they were near each other (which we avoided).

Strategy 3: Although our son loves playing with his sister, we kept them in different rooms for ~5 days with limited interaction in our backyard. My wife and daughter ate meals first (to limit their exposure to aerosolized particles in the dining room) before my son and I ate.

I took primary care duty for my son, whereas my wife spent more time with our daughter. We figured it was better if only one of us got sick, instead of both.

Strategy 4: Vaccines. My wife and I received Novavax boosters 4 months prior. Studies suggest effectiveness of NVX boosters last 6+ months. With my heterologous boosting (primary was Moderna and Pfizer boost #1), I was likely in the protective window.
academic.oup.com/cid/advance-ar…

For myself as primary caregiver of a squirmy, coughing toddler, I knew I’d likely be exposed at some point during the infection course. My goal was to have a minimal viral load at first exposure, so as to allow my B cells time to ramp up and generate antibodies.

Most of the COVID vaccines induce robust B cell responses and humoral immunity, but immune responses take 2-3 days to fully kick in. By minimizing the initial exposure, you may provide your body time for a systemic immune response before the virus becomes systemic itself.

Some refs:


nature.com/articles/s4154…
science.org/doi/full/10.11…
journals.plos.org/plosone/articl…

I give vaccines much credit for staying negative, as during one coughing-induced middle-of-the-night cry session a few days into his infection, I had forgotten my mask in my bedroom and only realized it after holding him for a few minutes.

I should add that we all tested daily. For my son to track his relative course – as predicted the test lit up around day 3, then quickly subsided and turned negative on day 5-6. We eased up on precautions around then, but maintained open windows and stayed outdoors when possible.

Lesson 6. Masking, ventilation, and staying up to date on your vaccines provides multi-layered protection against infection. If you are worried about vaccine side effects, the Novavax option is a traditional platform with fewer side effects.

Even mild COVID can result in long-term persistence in the body, multi-organ damage (e.g. brain and heart damage), and long COVID. The benefit of these relatively simple protective measures outweigh the inconvenience, especially in high-risk settings.
.heart.org/en/news/2024/0…

Finally, I should note that this is just our experience. There is a good deal of stochastic luck in who gets infected and who doesn’t. We were grateful to avoid further transmission and to protect some high-risk. I hope this is helpful to some others as well.