Many individuals worldwide have received or are now eligible to receive one of the several COVID-19 vaccines available. Whether you are a proponent or not for getting the injection yourself, one can at least appreciate the speed and coordination that has gone into this public-health effort which will hopefully save many lives.
It seems though, that most people take vaccines for granted. What I mean by this is that we assume we have no real “role” to play in the antiviral effects that the vaccine has in our body. Just show up, get stuck in the arm, and leave — job done, right? (Don’t forget to claim your free donut though…sigh).
Perhaps not. Our behaviors outside of getting the vaccine could actually influence its effectiveness at reducing your chance of becoming infected or dying from something like COVID-19 (this in addition to how your behaviors influence your risk of getting infected with any illness in general, but I digress).
A specific example is sleep. In a recent commentary published in The Lancet Respiratory Medicine, sleep experts Christian Benedict and Jonathan Cedernaes argue (with data) that a poor night of sleep before or after a vaccination could possibly reduce its efficacy and therefore, sleep should be prescribed and prioritized in this particular context. They base their argument on a few published studies in addition to citing some well-known physiology of how sleep modulates our immune system.
Benedict and Cedernaes 2021
In terms of published literature — studies have found that restricting sleep to 4 hours per night for 4 consecutive nights reduced the antibody response to the seasonal flu vaccine in adults. Furthermore, adults who have a shortened sleep duration also experienced a reduced secondary antibody response to a hepatitis B vaccination.
Sleep after a vaccine may also be just as important. When participants in one study were allowed a full night of sleep after a hepatitis A vaccination, their T-cell response was nearly doubled compared to when they were kept awake.
The authors point out that this reduced acute antibody response does not necessarily predict long-term efficacy of the vaccine against a virus, and most healthy individuals may still reach the “clinical threshold” response even in the setting of poor sleep. However, immunocompromised individuals may stand to benefit from prioritizing adequate sleep before and after vaccination to ensure a robust immune response that affords them protection against future infection.
What’s the mechanism? Sleep promotes the release of pro-inflammatory cytokines which increase helper T-cell responses, facilitating the transfer of antigenic information from a vaccine into antigen-specific T-cells.
Besedovsky et al., 2011: Pflugers Arch – Eur J Physiol (2012) 463:121–137
The “offline” condition of sleep — in particular slow-wave sleep (SWS) — is characterized by high levels of growth hormone and prolactin, and lower levels of cortisol and catecholamines (stress hormones). This helps the regenerative and adaptive function of the immune system operate better and, in someone who has recently been vaccinated, form an immunological memory against the antigen and in the long term, possible protection against a virus. This is no different than how sleep can boost neurological memory — take a nap after studying and you’ll tend to remember the information better.
All of this does not imply that a vaccine is worthless if you are sleep-deprived, but is at least some evidence that you may not get the “full effect” of the COVID-19 vaccine if you’re coming off of a night of inadequate sleep. It is also important to note that there have been no studies specifically on sleep and the COVID-19 vaccine, only other types of vaccinations.
If most of us know when our first/second dose of the vaccine is going to be scheduled, it could potentially be a time to prioritize a full night of sleep before, and ensure a full night of sleep after (obviously, I advocate getting a full night of sleep every night, but life happens). In addition, scheduling a vaccine for the morning may result in it also having a greater effect, perhaps due to the circadian oscillations of our immune system.
Other lifestyle behaviors like exercise have also been shown to impact vaccine efficacy. Really — and perhaps this is obvious — living an all around healthy lifestyle is going to have immune system benefits, whether you choose to get a vaccine or not. This is something that, unfortunately, has not been prioritized or talked about (at least in the popular culture) enough, but needs to attain a higher relevance in the minds of public health professionals and anyone interested in this topic. That is, if we wish to improve population health on a large scale in a way that has lasting effects.
Benedict C, Cedernaes J. Could a good night’s sleep improve COVID-19 vaccine efficacy? The Lancet Respiratory Medicine. Published online March 2021:S2213260021001260. doi:10.1016/S2213-2600(21)00126-0