The vaccine and vitamin D

Vitamain D is necessary in order to mount a strong immune response to the Covid-19 vaccine.

Since April 2020 there have been a significant number of studies from around the world examining the possible association between vitamin D status and susceptibility to COVID-19 and its consequences.

Many are retrospective cohort analyses, and some are prospective studies involving sufficiently different patient populations, with varying degrees of severity of symptoms and prognoses.

Better outcomes

What has been emerging has been that a higher vitamin D status is generally associated with a lower susceptibility to COVID-19, and better morbidity and mortality outcomes. ***

But we still need vitamin D – even with the vaccine!

The aim of a vaccine is to provoke an immune response – and the role of vitamin D in supporting both innate and adaptive immunity is well recognised.

It would be a shame to have the vaccine – but not be able to get the most out of it – due to a vitamin D deficiency.

Ongoing ability

Adequate vitamin D is necessary – not only for the initial response to the vaccine – but also for the ongoing ability of the immune system to generate antibodies and T cells in the future.

So this would be a good time to check on your vitamin D status. It could be the best health investment you’ll ever make.

It’s worth remembering that almost one in five adults aged 19 – 65 years in the UK has a low serum vitamin D concentration according to the National Diet and Nutrition Survey (NDNS).

The Scientific Advisory Committee on Nutrition (SACN) reported that on average 30–40% of the UK population has concentrations below 25 nmol/l in winter compared to 2–13% in summer.

However, a substantial percentage of some population groups do not achieve a plasma concentration more than ≥25 nmol/l even in summer. And this level is much lower than that recommended for optimal immune function. An adequate level needs to be at least 50 nmol/l.


It is also worth remembering that medicines strip our bodies of vital nutrients, especially vitamin D. The classes of medications that affect vitamin D status are significant and range from anticonvulsants to certain antihypertensive and diabetes drugs, as well as corticosteroids, and those used to treat gastric reflux, to name but a few.

Moreover, as many of these drugs are co-prescribed to treat multiple co-morbidities, especially in the elderly, their cumulative impact can further add to issues of vitamin D deficiencies. This will be the case for many older people – among whom vitamin D deficiency is even more widespread.

Level in the blood

Even if you’ve been taking vitamin D – it’s still worth getting tested. It’s not the amount of vitamin D you’re taking each day – but the level of vitamin D in the blood that counts. The only way to be sure of that is by testing.

If it turns out your vitamin D level is adequate – then you have the reassurance of knowing that. However, if it turns out you are deficient then you can do something about it. You can adjust the amount of your vitamin D supplement accordingly.

Roll on summer when we can get out in the sunshine and get our vitamin D that way!

Click here for details of testing


***    Click here to download a PDF of a study published in the Lancet on 22 Jan 2021. The study, conducted by the Hospital del Mar, Barcelona, Spain demonstrated that calcifediol (the active form of vitamin D) reduced deaths by 60% in COVID-19 patients. (See online)