Could Nigeria's HIV rate be just half what was thought?

LAGOS, Nigeria — The preliminary results of one of the largest HIV surveys ever undertaken suggest the disease could be just half as prevalent in Nigeria as previously thought.

Africa’s most populous country had already been marked as successful in reducing its rate from 3.7 percent in 2002 to 2.8 percent in 2017, according to estimates from the United Nations’ dedicated agency UNAIDS.

But the recently released preliminary results of the Nigeria HIV/AIDS Indicator and Impact Survey, or NAIIS — which cost about $100 million, involved 185 survey teams, and covered more than 200,000 people — show the national HIV prevalence as 1.4 percent among adults aged 15–49 years.

The survey was led by the government of Nigeria, and funded by the United States and the Global Fund to Fight AIDS, Tuberculosis and Malaria.

It suggests there are 1.9 million people under the age of 64 living with HIV in Nigeria — a 40 percent reduction from the country’s official national HIV prevalence estimates for 2017.

Those involved in the project say it is more accurate than previous surveys, since it is based on an expanded surveillance system and a revised and enhanced methodology.

Nigeria’s President Muhammadu Buhari said in a statement that the result reflected the progress Nigeria has made in scaling up HIV treatment and prevention services in recent years, claiming that “the end of AIDS as a public health threat by 2030 is truly in sight for our country.”

Advocates also say the new data will allow Nigeria to better target its HIV interventions in pursuit of the 90–90–90 goals set by UNAIDS and its partners. The goals are: to diagnose 90 percent of all HIV-positive people; to provide antiretroviral therapy for 90 percent of those diagnosed; and to achieve viral suppression for 90 percent of those treated by 2020.

The new results show that among adults living with HIV who have access to treatment, 42.3 percent have achieved viral suppression — when the HIV load is lowered to undetectable levels.

But they also show that women are more at risk than men. In particular, women in their early 20s are four times more likely to have HIV than men of the same age.

Why the numbers are improving

UNAIDS attributed the developments to a constellation of actions that have had a cumulative effect.

“The number of sites providing treatment has more than tripled, the number of sites providing services to prevent mother-to-child transmission of HIV has increased eightfold, and the number of HIV counselling and testing sites has increased fourfold. A total of 11.3 million adults were counselled and tested for HIV in 2016, four times as many as in 2012,” the agency said in a statement.

The U.S. government, which is actively involved in the country’s various HIV programs, also lauded the progress suggested by the results. “The encouraging results … will help Nigeria to intensify efforts in the fight against HIV/AIDS to achieve epidemic control,” said Mahesh Swaminathan, Nigeria country director at the Centers for Disease Control and Prevention.

But several experts added that the results should be interpreted with caution. Alfred Dede, a team lead manager at NAIIS, said the figures are estimates based on sample populations used to extrapolate for the entire country. While this is a scientifically acceptable method, it has limits. For example, he said, “in one state, due to the fact that mapping and listing were done by the National Population Commission, which already has its enumeration area and map, the survey may have been carried out in areas where prevalence and incidence [are] next to zero. Cluster sampling has its flaws.”

One major concern is the survey’s apparent silence on Nigeria’s key populations — those most at risk of HIV infection, including men who have sex with men, sex workers, and people who inject drugs.

For example, about 25 percent of gay men in Nigeria are HIV positive but due to laws against same-sex relationships and frequent discrimination, they often struggle to access treatment. Onyekachi Onumara, senior officer at the Rural Health Foundation, told Devex that experience in the field suggested the HIV infection rate among this group has not slowed. “We are still recording high numbers of new cases,” he said.

NAIIS field workers said that although some members of key populations were likely covered by the survey, they were not specifically targeted. Advocates argued that some groups in particular — such as brothel-based sex workers — are unlikely to have been reached and that others from vulnerable groups may have held back from revealing their HIV status to field researchers.

UNAIDS, however, told Devex that further analysis of the data would provide a clearer picture.

“These are only preliminary results of the survey — once there has been more analysis of the data, there will be a better understanding of how the epidemic is affecting different segments of the population, including key populations who were included in the survey,” a spokesperson told Devex.

And the director-general of Nigeria’s National Agency for the Control of AIDS, Dr. Sani Aliyu, said the agency has a separate key population size estimate survey that will complement the NAIIS and triangulate the data available “to give us more robust estimates of key population prevalence.”

What’s next?

Some HIV care providers worry the results could give donors the impression that the situation in Nigeria is under control and accelerate a gradual reduction in funds, which had already been a concern.

UNAIDS said this would not be the case. “The results of this survey still indicate that Nigeria has one of the largest HIV epidemics in the world but the data provides a much better understanding of the epidemic that will permit a more effective and efficient provision of services to people and places in greatest need,” the spokesperson said.

Aliyu added that — now success is in sight — stakeholders need to come together and identify funding streams that will increase the number of people on treatment.

“The NAIIS survey showed that our country’s epidemic is half the size we previously expected. Therefore the resources required to reach the 90-90-90 are far less than we estimated,” he told Devex, adding that local authorities should study the results to inform new strategies.

For President Buhari, the NAIIS result should spur players not to relent but to increase momentum.

“Let us work collectively and push for the last mile,” he said.