Friday, April 20, 2018
Saturday, April 07, 2018
Saturday, January 27, 2018
Neisseria meningitidis is a very common microbe, mostly residing in the throat of carriers without causing any harm. It is estimated that around 10% of people have it. Transmission is by droplets of saliva as when breathing into another person's face, sharing of eating utensils, sneezing without covering the face and poor hand hygiene.
Problems arise when Neisseria starts to multiply uncontrollably such as in people with weakened immune systems. There are 5 subtypes of this meningitis microbe, namely ABCWY. Up till recently there was a vaccine available for subtypes ACW and Y. Subtype B was not covered. This situation changed when a shot targeted at the B subtype became commercially available and the demand for it was (and still is) huge. This in part was aided by news stories of deaths in children having been stricken by meningitis B and the consequent emotional outpour duly amplified on social media platforms such as Facebook and Twitter. In Malta you had people going over to Sicily with cooler bags to buy the vaccine and bring it over.
A close look at the facts reveals that IMD is a rare disease with two major peaks of incidence. The first occurs in the first year of life and the second peak towards teenage. The first peak is much more significant than the second. Furthermore the currently available vaccine covers against around 80% of type B Neisseria meningitidis and the duration of immunity beyond 48 months is unknown. This means that widespread use of this vaccine will presumably cause natural selection for the uncovered 20% of strains, thus rendering the vaccine useless in the long term.
Two respected internationally recognised organisations have issued different recommendations with regards immunisation with meningitis B vaccine in healthy individuals. These are the British NHS and the Center for Disease Control (CDC) of the United States. The NHS recommends that the meningitis B vaccine is given to all children in the first year of life together with the other routine vaccines. This approach assures protection during the age wheninfection with the meningitis B bacterium is most likely. However there is no assurance that the child will remain covered through life. CDC on the other hand recommends giving the vaccine to children as they reach teenage.
One should note that the vaccine is considered safe to all effects but it does carry the risk of side effects such as pain at injection site, fever, loss of appetite and nausea.
So in conclusion I have to say that the development of this vaccine has been a welcome development, but more research is needed to increase the range of protective cover it provides and to elucidate the length of immunity it affords.
Wednesday, February 01, 2017
- it has to be an important health problem
- the natural history of the disease is well known
- it has to have a recognizable preclinical asymptomatic stage
- tests that can detect the preclinical stage are available
- offering treatment after early detection is of proven benefit
- the process has to be cost effective
- screening has to be an ongoing process
- easier to perform1
- faster to perform1
- patients find it more convenient and acceptable1
- relatively inexpensive1
- has relatively high sensitivity and specificity4
- target an entire population
- target only those at risk of a disease
- screen opportunistically
- screen haphazardly
- lifestyle and dietary advice
- pharmacological treatment
- referral to secondary care
- formulation of a clear policy on screening including all the stakeholders which should be reviewed periodically as new evidence materializes
- carrying out randomized controlled trials(RCT) on the efficacy of screening, or if this is not feasible logistically and economically, participating in any which may be currently running
- carrying out a feasibility study comparing early detection versus other preventive and therapeutic options
- haphazard screening should be discouraged
- those being screened should be given an explanation as to why they are being tested
- testing should be done with investigations of adequate sensitivity and specificity
- addressing the psycho-social needs of those testing positive and negative
- the screening should take into consideration the epidemiology of diabetes type 2 and related cardiovascular complications
- screening should take into account competing health priorities
- the screening being carried out should be formally evaluated
- Diabetes Care January 2002 vol. 25 no. 1 s21-s24
- Am Fam Physician. 2010 Apr 1;81(7):863-870.
- Personal professional experience in Primary Health Care
Thursday, December 29, 2016
This is the time of year when people gather to wish each other happy Christmas and good things for the coming year. It is also the time of one of the commonest respiratory infections. Influenza.
Influenza is caused by a virus of the same name which annually resurfaces to confine millions of people to bed. Each year the virus is slightly different from the previous year due to the process of genetic mutation. Its transmission is through droplets emitted from the mouths and noses of sick people. Cold temperatures cause people to aggregate in closed spaces making droplet transmission easier. Furthermore the body's defence of expelling harmful microbes is rendered inefficient by the cold.
Historically influenza has been responsible for various epidemics which have left millions of people dead. This fortunately is no longer the case thanks to advances in public health and general hygiene.
When one gets this disease he or she starts experiencing the symptoms of sore throat, runny nose, dry cough, fever and marked lethargy. These can last from three to seven days usually but can be prolonged if there are complications such as secondary infections.
A vaccine does exist which offers protection which lasts just one season. Re vaccination is necessary each year to maintain protection. It is most indicated for persons who have impaired immune systems, such as the elderly and those with chronic medical conditions, but in reality anyone over the age of six months will benefit.