The truth about vaccines: Here’s what really happens if you skip your shots

What are vaccines, and how do they work?

Vaccines are not medications in the traditional sense, and they don’t cure a disease you already have. Instead, they act like a rehearsal for your immune system. By exposing the body to a harmless version of a virus or bacteria (or a piece of it), vaccines train the immune system to recognize the invader. If you encounter the real infection later, your body is ready to respond quickly and strongly, often preventing illness altogether or greatly reducing its severity.

There are different types of vaccines, such as:

• Inactivated vaccines (e.g., flu) that contain killed germs.
• Live attenuated vaccines (e.g., MMR, measles, mumps, rubella) that contain weakened versions of germs.
• mRNA vaccines (e.g., COVID-19) that teach cells to make a harmless piece of the virus to trigger immunity.

No matter the type, all vaccines used in the UK must pass rigorous clinical trials and ongoing safety monitoring.

Why are childhood vaccines important?

For many, childhood vaccinations are their first line of defence against life-threatening diseases. Immunizations against measles, polio, diphtheria, and whooping cough protect against infections that once caused widespread illness and death.

Equally important, vaccinating children contributes to herd immunity, the collective protection that arises when enough people are immune, making it harder for diseases to spread. This is especially critical for those who cannot be vaccinated, such as infants or people with certain medical conditions.

Unfortunately, when vaccination rates fall, diseases that were nearly eliminated can resurface. Recent measles outbreaks in the country highlight the dangers of complacency. A single child missing a vaccine may seem harmless, but when large numbers skip doses, outbreaks follow.

Why do adults still need vaccines?

It may surprise some people to learn that immunity from childhood vaccines can fade over time. That’s why booster shots are necessary for continued protection against diseases like tetanus and diphtheria.

In addition, as new diseases emerge, like COVID-19, new vaccines are developed. Adults are also more vulnerable to certain illnesses as their immune system naturally weakens with age, making ongoing vaccination vital.

Commonly recommended adult vaccines include:

• Flu vaccine: Given yearly, especially important for adults over 65 and people with chronic illnesses.
• COVID-19 boosters: Updated formulations help protect against new variants and reduce severe illness.
• Pneumococcal vaccine: Protects against pneumonia and bloodstream infections, advised for adults over 65 or those with chronic heart or lung disease.
• Shingles vaccine: Recommended for adults over 70 in the UK.
• Tdap (tetanus, diphtheria, pertussis): Booster every 10 years.

Your GP or primary care provider can tailor recommendations to your personal health needs.

Are vaccines safe for people with chronic conditions?

For people managing conditions like diabetes, heart disease, chronic obstructive pulmonary disease (COPD), or autoimmune illnesses, the idea of vaccines can sometimes raise concerns. Yet these are often the very individuals who most benefit from vaccination.

Why? Because chronic conditions can increase the risk of severe complications from infections. For example, influenza can trigger heart attacks in vulnerable adults, and pneumonia can be life-threatening for those with lung disease.

Most vaccines are safe and strongly recommended for people with chronic health issues. If you are taking immune-suppressing medication, your doctor may recommend specific types or schedules. The important step is to have that conversation with your healthcare provider, not to skip vaccines altogether.

Are vaccine side effects normal, and should you worry?

It’s completely understandable to feel anxious about side effects. The good news is that most side effects are mild, short-lived, and a normal part of your immune system at work.

Common side effects include:

• Soreness or redness at the injection site
• Mild fever or fatigue
• Headache or muscle aches

These typically resolve within a couple of days. Serious side effects are extremely rare, and the NHS has robust monitoring systems to detect and investigate any potential issues quickly.

Think of side effects as proof that your body is learning how to defend itself.

How do vaccines interact with your medications?

If you’re taking medications, whether for blood pressure, diabetes, blood thinners, steroids, or cancer treatments, it’s natural to worry about vaccine safety.

Here’s what you should know:

• Most vaccines are safe to take alongside common medications.
• For people on immunosuppressants (like chemotherapy or biologics), timing may matter. Doctors may recommend scheduling vaccines before or between treatments.
• Some live vaccines may not be suitable for people with weakened immune systems.

Always discuss your vaccination schedule with your GP or healthcare provider. They can help balance your protection with your treatment plan.

Do vaccines make your immune system “weaker”?

This is a common myth, but the opposite is true. Vaccines strengthen your immune system by training it to recognize threats without causing the disease itself.

Even when children receive multiple vaccines at once, their immune systems handle them easily. In fact, kids encounter far more germs daily through play, food, and the environment than they ever do from vaccines.

Vaccines don’t “overload” your body; they fine-tune it to respond more effectively when real threats appear.

Can you catch the disease from the vaccine itself?

No, you cannot catch the disease from most vaccines. That’s because the majority use inactivated germs or only a piece of the virus or bacteria, making infection impossible.

The only exception involves live vaccines (like MMR or shingles), which contain weakened germs. Even then, they are carefully designed not to cause illness in healthy people. They are generally avoided in people with severely weakened immune systems.

So, while vaccines may mimic some symptoms as your body builds immunity, they do not give you the disease they are designed to prevent.

Why do some people avoid vaccines?

Vaccine hesitancy is not new, but the COVID-19 pandemic brought it into sharper focus. Some common reasons include:

• Worries about side effects.
• Confusion from changing guidance.
• A belief that natural immunity is “better.”
• Exposure to misinformation on social media or in daily conversations.

It’s natural to have questions about your health, and seeking information is a good thing. The challenge is separating fact from fiction. Reliable sources like the NHS and WHO consistently reaffirm the safety and necessity of vaccines. Talking directly with a trusted healthcare professional can also provide reassurance tailored to your situation.

What are the risks of skipping vaccines?

Choosing not to vaccinate can have serious consequences.

Personal risk

Unvaccinated individuals face a higher likelihood of contracting illnesses such as flu, COVID-19, or pneumonia. For older adults or those with chronic health issues, these infections often lead to severe complications, hospitalization, or even death.

Community risk

Diseases spread more easily when fewer people are protected. Vulnerable groups, including newborns, older adults, and those with weakened immune systems, rely on community immunity for protection. When vaccination rates decline, everyone is at greater risk.

The return of measles in multiple countries and rising COVID-19 hospitalizations when booster uptake falls serve as stark reminders of what can happen when immunization rates drop.

How often should you review your vaccination status?

A good rule of thumb is to check your vaccination record once a year, ideally during your annual GP or primary care visit. Keeping a personal record, whether on paper or via an app, helps ensure you don’t miss important boosters.

Pharmacists can also administer many vaccines, making it easier to stay up to date.

Key takeaways

Vaccines are not just for children, they’re a lifelong shield against preventable disease. From childhood immunizations to adult boosters, they protect individuals and communities alike.

For people with chronic conditions or those in older age groups, vaccines are especially valuable in reducing the risk of serious illness, hospitalization, and long-term complications. While mild side effects are common and normal, serious reactions are rare, and vaccines remain one of the safest tools in medicine.

They do not weaken your immune system, and you cannot catch the disease from most vaccines. Even if you take medications, vaccines are usually safe, but timing can matter, which is why checking with your healthcare provider is key.

The bottom line? Review your vaccination status regularly, stay informed through trusted medical sources, and don’t hesitate to ask your doctor questions. Choosing to stay up to date with vaccines is one of the simplest, safest, and most powerful steps you can take for lifelong health.

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Take care!