Drinking large amounts of water also does not reduce the risk of fainting for those with needle problems.
Here’s what we know about how water can affect vaccine response and overall health based on the available data.
Vaccine and water intake
Scientists have not carried out randomized studies to find out how taking – or not – water before vaccine administration affects antibody levels or other immune responses. This is a complex issue, partly because the immune response follows two main pathways: over the long term, it helps the body build lasting defenses against the virus; in the short term the vaccine also causes an “innate” immune response, responsible for the side effects that some people suffer after administration. Researchers have mixed views on the role of water in all of this.
Studies in frogs (distant human relatives) suggest that extreme dehydration can suppress the immune system making cell signaling more difficult, says Sonia Sharma, immunologist at La Jolla Institute for Immunology in California. In humans, dehydration can be one of several stressors and unhealthy behaviors that delays the production of antibodies, he adds. In addition, some research indicates that pain perception is greater when the subject is dehydrated, adds Jodi Stookey, a nutrition epidemiologist who worked at the Children’s Hospital Oakland Research Institute in California.
But drinking too much is also a health risk, as some studies show, as it causes sodium levels to drop and leads to headaches, fatigue, seizures and even death. Numerous experts argue that, except in the presence of high temperatures or in endurance sports, a healthy adult easily gets enough fluids through food and drink, even if he feels out of sorts for a day or two after the vaccine.
And while water is important in preventing kidney stones and urinary infections, people looking to maximize the immune response while minimizing side effects are unlikely to play a major role in this process alone. “Water is not the magic ingredient that can guarantee an optimal immune response,” says Sharma. “Taking the right amount of water is part of the virtuous behaviors for having a healthy immune system”.
Research carried out on athletes who practice endurance sports raises doubts about the possibility that water is able to influence the immune system in some way. We know that prolonged exercise such as running a marathon can produce an increase in stress hormones by reducing the function of white blood cells for a few hours. This exposes athletes more to disease after long exertion, says Michael Gleeson, professor emeritus of exercise biochemistry at the University of Loughborough in the UK who studies nutrition and immune responses to physical activity.
White blood cells include T and B cells in charge of identifying infectious agents, formulating a defense, and developing antibodies that can recognize and remember them. But when the researchers asked the athletes to drink more and maintain good hydration while running, their immune systems showed the same level of suppression as the dehydrated athletes.
“The idea that drinking lots of water can help reduce COVID vaccine side effects sounds ridiculous,” says Gleeson. “Water does not affect immune function”.
And drinking water doesn’t prevent fainting either. In about one in a thousand cases, the vaccine triggers a vasovagal reaction that causes dizziness, lightheadedness, and sometimes fainting within the first 15 minutes. Based on the fact that people are less likely to faint if they drink water before donating blood, Alex Kemper, head of pediatrics primary care at the Nationwide Children’s Hospital, in Columbus, Ohio, has prescribed hundreds of people between 11 and 21 years of age to drink up to two cups of water in the hour before the donation or vice versa to behave as usual. He found that drinking water did not change the incidence of dizziness or fainting. “The bottom line is that I didn’t notice any difference,” adds Kemper.
Enhancement of the vaccine effect
The questions related to hydration and vaccination response fit into a broader range of questions related to how much fluids we need to take, how to measure dehydration and whether it is important to force water intake in general. The data show that older people are more prone to chronic dehydration but the extent of the problem remains unclear.
Even assessing the state of dehydration remains a matter of debate. The sense of thirst may be sufficient, according to Kemper. “Millions of years of evolution have meant that, when we really need it, we drink,” he adds. “On a normal day we can let ourselves be guided by the sense of thirst to regulate our water intake. And we can probably apply the same criterion on the day of vaccination ”.
Given the uncertainty, the advice to drink water perhaps taps into people’s desire for control. It’s simple to do, and some experts find the advice to hydrate before vaccination harmless, if not beneficial if it helps motivate people to get vaccinated. “The more people we can vaccinate, the better it will be and if people want to drink water, it certainly won’t cause them any problems,” says Kemper. “People believe in the beneficial properties of water; if this makes you feel better, what’s wrong with that? “
However, there are those who worry that, if water is of no benefit, encouraging what is essentially a placebo effect could generate distrust in the medical system and lead them to think that normal side effects are something to worry about. Giving in to false health beliefs not based on scientific data can undermine the credibility of the health care system, adds Christopher Labos, cardiologist and epidemiologist at the Queen Elizabeth Health Complex in Montreal.
In his opinion, encouraging a person to drink water is more of a disservice than saying, “Your arm may sore but it will pass, don’t worry, it’s completely normal,” says Labos, who wrote about the false myths related to drinking. of water. “While it’s harder in the short term, being honest with people and telling them it’s a nonsignificant health problem is likely to produce more long-term benefits.”
In his work Labos says he receives many questions from patients about what to consume or avoid when administering the vaccine. “What we eat, drink or medications we take have no impact on the vaccine,” he says. “When it’s your turn, get vaccinated with peace of mind”.