Health

Does natural immunity from infection protect better than vaccination?

Natural immunity does not give better protection against diseases

World Immunisation Week, which falls on the last week of April every year, promotes the use of vaccines for all ages against various diseases, and the theme this year is Protected Together: Vaccines Work!

The campaign celebrates vaccine heroes around the world, from parents, community members, health workers, innovators and those who work hard to ensure that we are all protected through the power of vaccines.

Immunisation saves millions of lives every year and is widely recognised as one of the most successful and cost-effective health interventions.

Yet, there are many who still believe that natural immunity provides better protection for ourselves.

There are still nearly 20 million unvaccinated and under-vaccinated children in the world today, according to the World Health Organisation (WHO).

Some deadly diseases are also re-emerging, even though scientists had largely eliminated them with vaccines for decades.

Recent outbreaks of the oldest vaccine-preventable diseases such as measles, pertussis, diphtheria and polio in developed and developing countries are calling for global vigilance on immunisation programmes.

NATURAL IMMUNITY VERSUS VACCINATION

Contrary to popular belief, natural immunity is not better than immunity from vaccination.

Not all immunity which surfaces from the recovery of natural infections provide long-term protection.

Some natural infections such as pertussis (whooping cough) does not provide long-lasting immunity even after recovering from it.

The immunity wanes after many years, and the person might be susceptible to the infection again.

Routine immunisation provides a point of contact for healthcare at the beginning of life and offers every child the chance of a healthy life from the earliest beginnings and into old age, as vaccines are timed at a particular age to prevent severe complications from an infection.

For example, BCG vaccination against tuberculosis is given at birth, when the baby is most prone to severe complications.

Vaccination is a planned event that is safe and generally well-tolerated, while the outcome of natural immunity from infection is less predictable. For some, the infection may result in severe complications and long-term consequences, including death and organ failure.

'HERD IMMUNITY'

When a high percentage of the community is vaccinated, fewer people get infected and there are fewer chances for infectious diseases to spread.

This is called 'herd immunity', which allows protection to be extended to those who are too sick or too young to be vaccinated. But it only works if most people in the community are vaccinated.

VACCINATION IN SINGAPORE

Our National Immunisation Programme includes immunisation against many vaccine-preventable diseases, such as tuberculosis, hepatitis B, diphtheria, pertussis, tetanus, polio, pneumococcal disease, measles, mumps, rubella and Human Papillomavirus infection.

These illnesses can be deadly, especially among those who are vulnerable, like very young children, the elderly, pregnant women and people with chronic medical conditions.

The National Immunisation Registry (NIR) of Singapore is designed to collect and maintain complete and up-to-date vaccination records of children and adults who reside in Singapore.

To promote effective and cost-efficient disease prevention and control, NIR aims to achieve 95 per cent coverage for immunisations under the National Immunisation Programme.

Immunisations for diphtheria and measles are compulsory by law in Singapore.

Most of the recommended childhood vaccinations are provided free at polyclinics.

For the rest of the recommended childhood vaccinations, parents can pay using their MediSave, Childhood Development Account (CDA) or Baby Bonus.

While the coverage for vaccinations under the National Childhood Immunisation Programme has been high for most of the vaccines, there is low awareness on the benefits of adult vaccination for personal protection and the protection of vulnerable family members.

In a bid to boost awareness of the importance of vaccinations among adults, the Ministry of Health (MOH) has drawn up a list of recommended immunisation for various groups of patients aged 18 and above.

Singaporeans can use up to $400 from their MediSave account annually to pay for seven vaccines - Influenza, Pneumococcal (PCV13/PPSV23), Human Papillomavirus, Tetanus, Diphtheria and Pertussis (Tdap), Measles, Mumps and Rubella (MMR), Hepatitis B and Varicella.

All these are covered under the National Adult Immunisation Schedule (NAIS) at MediSave-accredited healthcare institutions such as hospitals, polyclinics and Community Health Assist Scheme (CHAS) GP clinics.

Immunisation is a shared responsibility. Ensuring that we are vaccinated will protect ourselves and our communities.

The writer is a family physician at SingHealth Polyclinics (SHP) and a member of SHP Infection Prevention and Infectious Diseases Workgroup

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