Healthy at Oktoberfest: Immunity & Vitamin C

When the tents open on the Theresienwiese for Wiesn, Munich’s Oktoberfest, large numbers of people come together in close quarters. Oktoberfest 2026 runs from 19 September to 4 October. For Munich residents, commuters from the surrounding area and visitors, crowded underground trains, late evenings and gatherings in festival tents are often part of the experience. These also create opportunities for respiratory pathogens to spread more easily. [1] [11]

Vitamin C, echinacea or a supposed ‘immune booster’ are often expected to provide protection at short notice. But the immune system cannot be boosted in advance to build up a reserve of protection. People who already get enough nutrients do not automatically benefit from additional supplements. And anyone who is ill unusually often or for a long time first needs a careful assessment of their symptoms. [2] [3]

At Praxis Schleicher in Munich, we therefore focus on this question: Is there a treatable cause of the susceptibility to infections, and which examination will actually help?

Why vitamin C alone does not prevent colds

Vitamin C contributes to the normal functioning of the immune system. However, this does not mean that taking large additional amounts prevents colds. In the general population, regular supplementation does not reliably reduce the risk of catching a cold. Illness may be slightly shorter; if supplementation only begins when the first symptoms appear, a benefit has not been consistently demonstrated. [2]

With echinacea and other products marketed as ‘immune boosters’, the specific product, the available research and potential interactions also need to be considered. Herbal does not automatically mean suitable or free of side effects. A confirmed deficiency is different from taking a supplement as a precaution without an identifiable need. [3]

A healthy immune response needs coordination

The immune system has to recognise pathogens, respond appropriately and then bring inflammation back under control. T cells, B cells and natural killer cells are among those involved. Regulatory mechanisms are part of healthy immune defence: they help prevent excessive reactions.

A single elevated or reduced cell count therefore does not explain why someone is frequently ill. Symptoms, the course of the illness and the findings as a whole are what matter. ‘More activation’ is not a universally appropriate treatment goal. [4] [5]

When frequent infections should be investigated

A respiratory infection after several days of contact with many people does not in itself mean that you have an immune deficiency. The number of colds alone is also insufficient to make that assessment. The types of infection, their severity, duration and possible complications are more informative. [4]

Medical assessment is particularly helpful when infections are unusually severe or prolonged, pneumonia occurs repeatedly, unusual pathogens are identified or a persistently unusual pattern of illness emerges. A family history of an immune deficiency disorder may also be relevant. [4]

Persistent exhaustion after infections also deserves attention. However, it does not prove an immune deficiency. Alongside immunological causes, sleep problems, anaemia, existing illnesses and medication effects, for example, need to be considered.

Immune assessment: targeted testing rather than measuring everything

Diagnosis begins with a consultation and physical examination. Which infections have occurred? Were any pathogens identified? How long did the symptoms last? Which medicines are you taking? Previous medical letters and laboratory results, together with a brief record of illnesses, can be helpful.

If there is a justified suspicion of an immune disorder, basic investigations include a differential blood count and measurement of key antibody classes, particularly IgG, IgA and IgM. Further tests depend on the clinical suspicion and the results obtained so far. [4]

Lymphocyte subset testing can show the numbers and distribution of different immune cell groups in greater detail. These include:

Helper T cells (CD4): involved in coordinating immune responses.
Cytotoxic T cells (CD8): can recognise and eliminate virus-infected cells, among other functions.
B cells: can develop into antibody-producing cells.
Natural killer cells (NK cells): part of the innate immune system.

It is important to distinguish between cell numbers and cell function. A routine cell count does not automatically measure how well those cells work. Functional tests and investigations of specific subsets, such as regulatory T cells, require a specific clinical question. They are not a routine preventive check before visiting Oktoberfest. [5]

Timing, acute infections and medicines can also influence laboratory results. Abnormal values are therefore assessed in context and checked again if necessary. A single laboratory value cannot establish an overall ‘immunity score’ or automatically determine the right treatment. [5]

Identifying deficiencies and treating them specifically

In the case of recurrent infections or delayed recovery, it may be helpful to look for a nutrient deficiency as well. Which values are tested depends, among other things, on diet, symptoms, pre-existing conditions and findings already available. A comprehensive micronutrient panel is not necessary for everyone.

Interpreting ferritin, vitamin D and vitamin B12 correctly

Iron and ferritin: Ferritin provides information about iron stores. However, inflammation can raise the value and mask an iron deficiency. It is therefore assessed together with the blood count and, where appropriate, further iron and inflammation markers. Iron should not be supplemented without findings that justify it. [6]

Vitamin D: Testing may be useful where there are specific risk factors or a medical question to answer. Routine screening without an indication is not recommended in otherwise healthy adults. A low result is also not automatically the explanation for every cold. [7]

Vitamin B12: A deficiency can impair blood formation and the nervous system, among other things. Risk may be increased, for example, by a vegan diet, certain absorption disorders or particular medicines. Testing is guided by the individual clinical suspicion. [8]

If a deficiency is confirmed, its causes are also considered. The type, dose and duration of treatment depend on the findings. Oral preparations are often an option. An infusion is not inherently more appropriate simply because it bypasses the digestive tract; it needs its own medical justification and an assessment of benefits and risks.

Immunomodulation is an individual treatment decision

Immunomodulation means deliberately influencing an immune response. Whether such treatment is appropriate depends on the diagnosis, the specific preparation and the evidence available for it. Reduced cell counts alone do not demonstrate that stimulation will help.

At our practice, we discuss with you which measures follow from the findings. These may include treating an underlying illness, correcting a specific deficiency or, where indicated, further treatment. An individual treatment plan takes potential side effects into account and sets out when progress should be reviewed.

Certain bacterial lysates have indications for preventing recurrent respiratory infections. This does not justify a general recommendation for all ‘gut’ or ‘immune’ preparations. According to the European assessment, the lysates concerned are not intended to treat an existing respiratory infection or to prevent pneumonia. The current information for the particular medicine remains decisive. [9]

This does not support a promise that a course of injections or infusions will make you ‘Oktoberfest-ready’ at short notice.

Practical steps you can take during Oktoberfest

There are useful steps for the coming weeks even without specialised testing:

Make time for sleep: Sufficient, regular sleep supports normal immune function. Late nights at Oktoberfest should not lead to persistent sleep deprivation over several days. [10]
Eat regularly and choose non-alcoholic drinks: Varied meals help meet your nutrient needs. Plan for water and alcohol-free alternatives. Alcohol is not a way to prevent infections.
Reduce transmission risks: Wash your hands, ventilate indoor spaces and reduce contact with others when acutely ill. If you have a fever or feel clearly unwell, postpone your visit to the festival tent. [11]
Review your vaccination status: Which vaccinations against respiratory diseases are recommended depends, among other things, on age and pre-existing conditions. This can be discussed using the current recommendations of Germany’s Standing Committee on Vaccination (STIKO). A vaccination the day before Oktoberfest does not provide immediate protection for the opening day. [11]

Infection prevention and immune defence complement each other

A well-fitting mask can reduce the risk of transmitting respiratory pathogens. This can be particularly relevant in crowded indoor spaces, when contact cannot be avoided despite having symptoms, or to protect people at increased risk. Fit and mask type influence the protection provided. [12]

The fact that a mask does not treat nutrient deficiencies does not diminish its usefulness. It reduces exposure; diagnosis and treatment address possible causes of symptoms. Deliberately accepting respiratory infections is not a recommended way to ‘train’ the immune system.

Medical assessment in Munich-Bogenhausen

If you become ill unusually often during autumn or do not recover for a long time after infections, Oktoberfest season can be an opportunity to discuss your history with a doctor. A meaningful assessment is also possible during and after Oktoberfest. Depending on the clinical question, it takes time and offers no guaranteed immediate protection.

At Praxis Schleicher, Ismaninger Straße 65 in Munich-Bogenhausen, we discuss with you which investigations are indicated for your symptoms. We also welcome patients from the wider Munich area. Existing findings and a list of your medicines help avoid duplicate testing.

Would you like to have recurrent infections or persistently delayed recovery assessed? Book a medical consultation. Together, we will discuss which investigations are appropriate and what treatment follows from them.

Book an assessment

Praxis Schleicher · Ismaninger Straße 65, 81675 München
Phone: 089 4194530 · praxis@praxis-schleicher.de

If you experience severe shortness of breath, chest pain or rapid deterioration, seek medical help immediately; do not wait for a routine consultation.

Staying well during Oktoberfest in Munich: Why your immune system needs more than vitamin C