One of the discoverers of HIV has suggested that people with suppressed immune systems, including people with HIV, may be more vulnerable to Severe Acute Respiratory Syndrome (SARS).
Speaking at a press conference in Tokyo, Prof. Luc Montagnier said that SARS could have more serious health implications for people with HIV, and that the mortality rate amongst people with HIV who have reduced immune function, would be higher than the 4% currently being observed. Southern China, where SARS is thought to have originated, has a high HIV prevalence, but it is not known if anybody who has been infected with the virus is also HIV-positive.
Prof Montagnier did, however, point out that SARS and HIV are two completely different viruses, and that with a mortality rate of no more than 5% the virus “hasn’t got much chance of going far” and that influenza killed many more people each year.
SARS is thought to have originated in China in November last year and to have spread around the world by air travel in February. So far around 3,500 cases have been recorded worldwide and 200 deaths have been attributed to the virus.
Symptoms are similar to flu and include a high temperature, headache, sore throat and cough. Pneumonia has developed in some cases, causing breathing difficulties requiring artificial ventilation. However, the overwhelming majority of people (80-90%) who become ill with SARS make a full recovery within a fortnight.
The virus which causes SARS is thought to be a variant of the corona virus, which causes common colds. Like a cold, it is believed to be spread by coughing and sneezing, although very close contact with an infected person is thought to be necessary to contract the illness, according to a series of reports in the New England Journal of Medicine. It is also thought that cockroaches helped spread the virus around an apartment block in Hong Kong, and like coughs and colds, it may also be possible to transmit SARS when people touch objects after coughing or sneezing onto their hand.
People who have died of SARS have tended to be over 40 years old, and it is therefore theorised that others with suppressed immunity, such as people with untreated HIV, may be more vulnerable to the disease. As people with HIV whose immune system has been restored by HAART seem no more vulnerable to common colds, it may be reasonable to assume that they will be no more likely to become ill with SARS than HIV-negative people. However, Hong Kong health authorities have expressed concern that at least six SARS deaths in that city have occurred in `young, fit` individuals.
Prof. Montagnier suggested that the best way of avoiding infection with the virus was to boost the immune system. Airlines flying to east Asia and other infection “hot spots” have put in place infection control procedures, such as stopping people who look ill from traveling and some east Asian countries have introduced quarantine procedures.
There have been no deaths from SARS, and only a few dozen cases, in the UK and Europe. The UK Department of Health is strongly advising people not to travel to Hong Kong or the Guandong province of China (although Vietnam, Singapore and Canada also have growing outbreaks, as do the Chinese cities of Beijing and Shanghai). People returning to the UK from an affected area are recommended to see their doctor urgently if they suddenly develop a high temperature, or symptoms suggestive of pneumonia, including dry cough, shortness of breath, as well as muscle aches and sore throat, within ten days of their return. There is no special advice for people with HIV.
Laboratories in Europe, China and North America are attempting to develop an antibody test that will show whether individuals have been exposed to the virus now believed to cause SARS. These tests are likely to be available within one to two weeks in some countries, including the United States.
Editorial comment
It is worth noting, that despite the huge media attention the SARS outbreak has received, more people died of malaria in a single day than have so far been reported with SARS.
Parallels have been drawn with the Spanish influenza pandemic of 1918-19. These should be treated with care. Although it is true that the 5% mortality rate of SARS is twice that of the Spanish influenza (which caused a worldwide pandemic after the First World War claiming up to 50 million lives) comparisons should take into account the improvements in healthcare made since then. In addition, the perceived severity of the 1918-19 epidemic is distorted by an uneven mortality rate, which approached 85% in some communities but remained low in others. Spanish influenza was complicated in many cases by high levels of tuberculosis in the population, whilst widespread bacterial pneumonia was ultimately the disease that killed many `flu victims`. In 1918-19, antibiotics did not exist to treat bacterial pneumonia.