On the health front, the year 2016 witnessed a few setbacks and but also a few positive developments. Here are the most important health developments of 2016
1. Trial results confirm Ebola vaccine provides high protection
The Ebola virus that killed more than 11,300 people in three West African countries — Guinea, Liberia and Sierra Leone has finally met its match.
In December, an Ebola vaccine trial carried out in 2015 in nearly 12,000 people in Guinea was found to be safe and highly protective against the deadly virus.
No Ebola cases were recorded in nearly 6,000 people who received the vaccine, while there were 23 cases in the arm that received the vaccine after a 3-week delay. The trial used an innovative design called a “ring vaccination” approach — the same method that was used to eradicate small pox. In the ring vaccination strategy, whenever a new Ebola case was diagnosed, all the people who may have been in contact with that person were traced and included in the trial.
The vaccine was found to have high efficacy even when the interim results were announced. So everyone included in the trial was offered the vaccine immediately, including children older than 6 years.
A total of 28,616 Ebola cases and 11,310 deaths have been reported in three countries, as on June 2016.
2. HIV self-testing gets a shot in the arm
Access to and uptake of HIV diagnosis got a shot in the arm when the WHO in November released new guidelines on HIV self-testing. Lack of an HIV diagnosis has been a major obstacle in the war against HIV.
Today, 40 per cent of all people with HIV (over 14 million) are simply unaware of their status. While more than 18 million people with HIV are currently taking anti-retroviral treatment (ART), and a similar number is still unable to access treatment as many are not aware of their HIV positive status.
Only 30 per cent of men have tested for HIV. As a result, men with HIV are less likely to be diagnosed and more likely to die of HIV-related causes than women.
Testing also remains low among high-risk population such as men who have sex with men, sex workers, transgender people, injection drug users, and people in prisons. These people comprise nearly 44 per cent of the 1.9 million new adult HIV infections that occur each year.
People can use oral fluid or blood- finger-pricks to discover their status in the comfort of their house with no fear of being subjected to stigma and discrimination. This is bound to encourage more people to get tested.
Results are ready within 20 minutes or less. Those with positive results are advised to seek confirmatory tests at health clinics. Twenty three countries currently have national policies that support HIV self-testing. India is yet to approve HIV self-testing.
3. Zika virus and public health emergency of international concern
On November 18, the World Health Organisation declared that Zika virus is no longer a public health emergency of international concern. It was in February that the WHO declared the Zika outbreak and congenital malformations and neurological disorders in newborns believed to be caused by the virus as a global public health emergency. Brazil has been the worst affected by the virus.
A distinct pattern of birth defects caused by Zika infection during pregnancy is now officially known as congenital Zika syndrome.
In November, a study showed that a small group of Zika-infected babies in Brazil who were born with normal-size heads had developed microcephaly five months to a year after birth.
The virus that has caused about 2,300 confirmed cases of microcephaly (a congenital disorder where babies are born with a small head) since May 2015. The link between Zika virus and microcephaly was established in May this year. After the initial spread to 67 countries, including countries in Southeast Asia, the spread has since slowed down.
While Aedes species of mosquitoes is the primary vector that transmits the virus, it can also be transmitted though semen, blood, tears and other blood fluids. Unlike in the case Ebola, scientists are yet to find an efficacious vaccine against Zika virus. And we are yet to fully understand the entire spectrum of neurological problems that may show up in children born with microcephaly. Meanwhile, the WHO has advised that pregnant women refrain from travelling to countries where local transmission of Zika virus is still prevalent.
4. Incidence of TB in India increases sharply
Although global TB deaths dropped by 22 per cent between 2000 and 2015, TB is still one of the top 10 causes of death worldwide. It kills more people than HIV and malaria.
Of the estimated 10.4 million new cases worldwide, the estimated number of new cases in India alone has increased sharply from 2.2 in 2014 to 2.8 million in 2015. The true incidence in India will be known once the national TB prevalence survey scheduled to begin next year is completed. Besides the uptick in incidence, the number of estimated deaths caused by TB has also more than doubled from 220,000 in 2014 to 483,000 in 2015.
The sudden increase in TB incidence in India is due to 34 per cent increase in case notification between 2013 and 2015 by doctors in the private sector. Yet, in 2015, notification by private-sector doctors was only 16 per cent of the total case notification. Of the 2.8 million estimated cases each year in India, only 1.7 million cases both in the public and private sector were notified in 2015. So the remaining 1.1 million cases are simply not known.
5. Sri Lanka becomes malaria-free
In September, Sri Lanka achieved a huge public health success when the WHO declared it as malaria-free. There has been no local transmission nation-wide in Sri Lanka since October 2012. The WHO certifies a country as malaria-free when the chain of local transmission has been interrupted nationwide for at least three years. With this, Sri Lanka joins the ranks of 34 countries that have been certified as malaria-free since 1960s.
With no local transmission currently, Sri Lanka’s focus is on preventing the re-introduction of malaria from outside, particularly countries such as India, which are malaria-endemic. There were 95 re-introduced cased in 2013, 49 cases in 2014 and 36 cases in 2015.
Sri Lanka was able to win the war against malaria by targeting both the vector and the parasite. This was achieved by active detection of cases and targeting parasite carriers by screening people whether they had malaria symptoms or not.
It came to eliminating malaria in 1963 when it reported just 17 cases including six that were due to local transmission.
6. Thailand ends vertical transmission of HIV
In June, Thailand became the first country in the Asia-Pacific region to end vertical transmission of HIV from mother to child.
In 2000, an estimated 1,000 children in Thailand were infected with HIV due to vertical transmission. But in 2015, the numbers dropped dramatically to just 85, a decline of more than 90 per cent. The rate of mother-to-child transmission of HIV has been reduced to less than 2 per cent.
Thailand achieved this feat by ensuring that 98 per cent of all pregnant women with HIV had access to antiretroviral therapy. Women with HIV have a 15-45 per cent chance of transmitting the virus to their children during pregnancy, labour, delivery or breastfeeding if they are not on treatment during pregnancy. But the risk drops to just over 1 per cent if antiretroviral medicines are given to both mothers and children throughout the stages when infection can occur.
Treatment to prevent vertical transmission is not 100 per cent certain. So vertical transmission is considered to be eliminated when a country successfully achieves a reduction in transmission to such a low level that it no longer constitutes a public health problem.
Besides treating pregnant women with HIV with antiretroviral medicines, Thailand witnessed a sharp drop in the number of women in the child-bearing age becoming infected with HIV. Between 2000 and 2014, the annual number of women newly infected with HIV fell from 15,000 to 1,900 — an 87 per cent reduction.
7. Polio end game starts across the world
In April, 155 countries including India switch from using a trivalent oral polio vaccine that contains type 1, type 2 and type 3 strains to a bivalent oral polio vaccine that contains only type 1 and type 3 strains. The global vaccine switch took place between April 17 and May 1.
The reason for removing the type 2 strain from the vaccine was to confer better protection against polio. The oral polio vaccine contains live, weakened virus, which on rare occasions can turn virulent and cause vaccine-derived poliovirus. Though wild poliovirus type 2 was eradicated in 1999, all type 2 polio cases have been caused only by vaccine-derived polioviruses. The type 2 strain in the trivalent OPV had caused over 90 per cent of vaccine-derived poliovirus cases in the world in the last 10 years.
Polio, including vaccine-derived polio, can be eradicated only when oral polio vaccine is eventually withdrawn after wild polio transmission has been stopped. Removing type 2 strain from the vaccine and switching over to a bivalent vaccine is the “first major step” of this withdrawal process.
Science Chronicle 