Adult immunisation

A VACCINE induces immunity to a disease by stimulating the body’s production of antibodies.

Efficacy levels of vaccines range from 60% to 70%, to close to 100%.

According to the Malaysian Clinical Practice Guidelines on Adult Vaccination, the target groups for influenza vaccination are: residents of homes for the elderly; elderly folks with chronic conditions like cardiovascular, lung, metabolic, or kidney disease; adults and children (above six months old) who have chronic diseases; those at higher risk for complications; those who can transmit the disease to others, such as healthcare workers; and haj pilgrims.

Adults age 65 and above are at risk of serious diseases such as diphtheria, influenza, pneumococcus and tetanus (lockjaw). Certain sectors of society are more susceptible to particular infections.

Emeritus Professor Datuk Dr Lam Sai Kit said padi and pig farmers should get the Japanese encephalitis vaccine as they are at special risk of getting infected. The same goes for the typhoid vaccine for people involved in hawker businesses and food handlers.

“Adults who escape being infected by the chickenpox virus in childhood should consider immunisation against it. Quite often, they get much more severe infection, usually caught from their own children. The meningococcal meningitis vaccine and influenza vaccine are recommended for those going for the Haj.

One of the latest vaccines in the market is the human papillomavirus (HPV) immunisation for girls and women up to the age of 26. The HPV vaccine protects against four types of HPV that cause most cases of cervical cancer and genital warts.

Lam, who is senior research fellow at Universiti Malaya, said many young adults in the country have benefited from the Expanded Programme of Immunisation (EPI) implemented in 1989 and have been immunised against diseases like MMR and Hepatitis B.

“The EPI programme in Malaysia has successfully brought down the morbidity and mortality of these vaccine-preventable diseases, especially those of childhood,” said Lam, adding that Hepatitis A and B are two such vaccines under the EPI.

“Adults who have not been vaccinated against some of these diseases because they were born after the implementation of the EPI programme should consider doing so,” he said, adding that older persons have also received vaccines against BCG and smallpox.

He said adults who missed certain childhood infections such as chicken pox and measles should consider immunisation since the diseases in adulthood tend to be more severe.

“Smallpox is an excellent vaccine and used to eradicate the disease globally. Polio is the next disease for eradication, to be followed by measles.

“These diseases are ideal targets for eradication because the vaccines are good, easy to deliver, and there are no animal hosts.”

Some adults incorrectly assume that the vaccines they received as children will protect them for the rest of their lives. This is generally true but there are some caveats – some adults were never vaccinated as children, newer vaccines were not available when some adults were children, immunity can fade over time, and as we age, one becomes more susceptible to serious disease caused by common infections such as flu and pneumococcus.

“Many adults think that they are naturally immune to infectious diseases until they are struck down with dengue, chickenpox, mumps, rubella or influenza. It is also not true that the elderly and immuno-compromised adults do not respond well to immunisation,” said Lam.

Vaccine-preventable adult diseases include: cholera, diphtheria, Haemophilus influenzae type b (Hib), Hepatitis A, Hepatitis B, herpes zoster (shingles), human papillomavirus (HPV), influenza (flu), Japanese encephalitis, measles, meningococcal, mumps, pertussis (whooping cough), Pneumococcal, polio, rubella (German measles), tetanus (lockjaw), varicella (chickenpox) and yellow fever. –

Source: US Centre for Disease Control and Prevention / Malaysia’s Clinical Practice Guideline on Adult Vaccination