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By Dr. Priyom Bose, Ph.D. Reviewed by Danielle Ellis, B.Sc.

What happens after HIV infection?
Evolution of HIV diagnostic assays
Conclusions
References
Further reading

Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV) that attacks the body’s immune system, making it vulnerable to all infections. One of the major concerns of the early AIDS epidemic that began in 1981 was the lack of proper diagnostic measures to identify infected individuals.1 Since the development of the first HIV diagnostic assay in 1985, scientists have continued to improve diagnostic accuracy, detection speed, and cost.

Image Credit: Hanna Karpiak/Shutterstock.com What happens after HIV infection?

The immune system produces antibodies after encountering harmful foreign substances or antigens. HIV infects the vital cells associated with immunity, such as macrophages, helper T cells, and dendritic cells, and disrupts their function. The three important HIV antigens are p24, gp 41, and gp 120.2

HIV is a slow-replicating retrovirus that is transmitted through sexual intercourse, sharing an infected needle, or by blood transfer.3 After HIV infection, the viral load cannot be measured immediately due to low plasma load. Typically, the viral RNA can be measured within 10 to 12 days after infection.4

Antibodies to p24 and gp 41 are the first serological markers used to detect HIV infection. IgG antibodies appear approximately three weeks after infection. In the majority of HIV-infected individuals, HIV antibodies appear to circulate within 1 to 2 months of the infection. However, in a few cases, it may take up to six months to appear at a detectable level.5 Evolution of HIV diagnostic assays

Over the years, scientists have developed many immunoassays and nucleic acid amplification tests (NAATs) to accurately and high-throughput HIV diagnosis. These tests are broadly divided into two categories, namely, screening and confirmatory tests. Typically, HIV tests are performed on blood, oral fluids, or urine samples.6

HIV screening is performed by various immunoassays that focus on detecting IgG antibodies against HIV-1 antigens in the serum. Techniques such as Western blot, line immunoassay (LIA), and recombinant immunoblot are used as confirmatory tests.7 Some of the important HIV diagnostic assays are discussed below: Serological testing for HIV

In the mid-1980s, simple serological tests for HIV antibodies were developed based on culture-derived viral antigen preparation.7 These tests enabled HIV diagnosis and assessed blood and blood product supplies. Since the early assays, various serological assays have been developed that aided simple/rapid testing, high-throughput screening, confirmatory tests, incidence determination, and epidemiological surveillance. Since its first development, five generations of enzyme immunoassays (EIAs) have emerged based on varied antigen preparations and detection chemistries.8

First-generation assays: The first-generation EIAs detect IgG antibodies from antigens derived from whole viral lysates of HIV-positive cultures. Since crude antigen lysate contains impurities, this method exhibited reduced specificity and high false positivity. In contrast, immunofluorescence assays or Western blotting (WB) have shown higher specificity and lower false positivity.

Second-generation assays: Second-generation assays involve the use of recombinant proteins or synthetic peptides derived from the immunodominant regions (IDR) of HIV-1 proteins and gp36 of HIV-2, which increases sensitivity and decreases false positivity.

Third-generation assays: Third-generation assays, including the Genetic Systems HIV-1/HIV-2 Plus O EIA, use a variety of antigens to detect HIV-1 and -2 antibodies in the serum. A major advantage of third-generation sandwich format assays is their ability to detect HIV-1 IgM antibodies early, enabling quicker HIV diagnosis.

Fourth-generation assays: The fourth-generation EIAs, including the Abbott Architect HIV Ag/Ab Combo assay, utilize fully automated chemiluminescent microparticle technology that can instantaneously identify antibodies to HIV-1 and HIV-2 and HIV-1 p24 antigen. This technique has further allowed early HIV diagnosis. Other advantages of fourth-generation high-throughput assays are their capacity to perform more than 150 tests per hour and their ability to test specimens immediately upon arrival and generate results within 30 minutes.  These assays are suitable for facilities, such as blood banks, that handle high volumes of blood samples.

Fifth-generation assays: Fifth-generation assays, such as the Bio-Rad BioPlex 2200 HIV Ag-Ab assay, use magnetic beads coated with p24 monoclonal antibodies and epitopes specific for HIV-1 and HIV-2. This type of assay has a major advantage in  that it can confirm HIV infection in a single test. Interested in Assay Kits? Explore Equipment Here

Despite the advancements in EIA assays, the challenges associated with the generation of false positive results persist. Therefore, EIA-reactive specimen is typically retested with supplemental tests, such as Western Blot. Rapid diagnostic tests Related StoriesSweden exceeds UNAIDS HIV goals but faces new challengesNutrition's pivotal role in combating tuberculosis: addressing N-AIDS for better outcomes

The first HIV rapid test was available in the early 1990s. It determined an individual's serostatus before surgery, maternal labor/delivery, and organ transplant. Rapid diagnostics is based on immunochromatographic technology that uses blood from finger pricks to assess HIV status. 9 This test can provide results in less than 30 minutes and can be used in point-of-care (POC) settings. Since this test presents both false positive and negative results, it is essential to confirm the findings with laboratory-based HIV assays.

The main advantage of this technique is that any non-laboratory staff can perform it in a primary health care center. Even though decentralization of HIV diagnostic services has increased HIV test service in remote areas, it has been challenged by the lack of national guidelines, waste disposal, inventory management, and quality assurance (QA) monitoring.10

HIV self-testing, based on rapid testing methods, has allowed individuals who would otherwise refrain from testing in fear of discrimination to perform the test privately and start proper intervention. The World Health Organization (WHO) has prequalified several HIV rapid tests for HIV self-testing, including the Insti HIV-1/HIV-2 antibody tests and the Oraquick rapid HIV-1/2 antibody test.10 Nucleic acid test (NAT)

The NAT identifies HIV nucleic acid, i.e., either RNA or proviral DNA, in the blood sample. This test is based on the principles of polymerase chain reaction (PCR), nucleic acid sequence-based amplification, or ligase chain reaction.11 This test has proved to be vital in situations when an antibody against HIV is absent in serum. NAT is also performed in newborns of HIV-infected mothers. Unlike other assays, this test can detect HIV even after recent or possible exposure to the virus. Furthermore, NAT can quantify viral load.

Revolutions in Infectious Disease Testing Conclusions

The advancements in HIV diagnostic assays have played a vital role in identifying, staging, and monitoring infected individuals, even when they are under antiretroviral therapy. These assays have played an important role in surveillance and identification of transmission hot spots. Extraordinary progress in HIV testing methodologies has not only reduced false positives but decreased assessment time as well. References Sharp PM, Hahn BH. Origins of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med. 2011;1(1):a006841. doi: 10.1101/cshperspect.a006841. Foster JE., et al. Viruses as Pathogens: Animal Viruses, With Emphasis on Human Viruses. Viruses. 2018; 157-187. doi.org/10.1016/B978-0-12-811257-1.00007-3 Dasgupta A, Wahed. Human immunodeficiency virus (HIV) and hepatitis testing. Clinical Chemistry, Immunology and Laboratory Quality Control (Second Edition). 2021; 513-533. doi.org/10.1016/B978-0-12-815960-6.00015-7 Konrad BP, et al. On the duration of the period between exposure to HIV and detectable infection. Epidemics. 2017; 20, 73-83. doi.org/10.1016/j.epidem.2017.03.002 Davis LE. Acute viral meningitis and encephalitis. Infections of the Nervous System, 1987; 156-176. doi.org/10.1016/B978-0-407-02293-5.50014-3 Pant PN. Oral fluid-based rapid HIV testing: issues, challenges and research directions. Expert Review of Molecular Diagnostics. 2007; 7 (4), 325-328, DOI: 10.1586/14737159.7.4.325 Abdullah DM, et al. The contemporary immunoassays for HIV diagnosis: a concise overview. Asian Biomed (Res Rev News). 2023;17(1):3-12. doi: 10.2478/abm-2023-0038. Alexander TS. Human Immunodeficiency Virus Diagnostic Testing: 30 Years of Evolution. Clin Vaccine Immunol. 2016;23(4):249-53. doi: 10.1128/CVI.00053-16. Aidoo S, et al. Suitability of a rapid immunochromatographic test for detection of antibodies to human immunodeficiency virus in Ghana, West Africa. J Clin Microbiol. 2001;39(7):2572-5. doi: 10.1128/JCM.39.7.2572-2575.2001. Parekh BS, et al. Diagnosis of Human Immunodeficiency Virus Infection. Clin Microbiol Rev. 2018;32(1):e00064-18. doi: 10.1128/CMR.00064-18. Garrett, P. E. Quality control for nucleic acid tests: Common ground and special issues. Journal of Clinical Virology. 2001; 20(1-2), 15-21. doi.org/10.1016/S1386-6532(00)00150-5

Further ReadingAll HIV ContentThe Economic Impacts of AIDSRecent Advancements in Treating HIV

Last Updated: Nov 29, 2024

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Suspended Labour MP Mike Amesbury jailed after punching man in street

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Suspended Labour MP Mike Amesbury jailed after punching man in street

MP Mike Amesbury has been jailed for 10 weeks after punching a man in the street – and has been kicked out of the Labour Party.

The Runcorn and Helsby MP pleaded guilty in January to assault by beating of 45-year-old Paul Fellows in Main Street, Frodsham, Cheshire, in the early hours of 26 October.

Politics latest: ‘Alarm bells ringing’ for Labour

As well as a 10-week jail sentence, Amesbury, 55, must pay £200 compensation to Mr Fellows.

Amesbury had been drinking in the town in his constituency where he lives before arriving at a taxi rank, where Mr Fellows approached him to complain about the closure of the Sutton Weaver swing bridge.

The court heard how, after punching Mr Fellows in the head and knocking him to the ground, Amesbury punched him a further five times on the ground before members of the public intervened.

As he was being held back, he told Mr Fellows: “You won’t threaten your MP again, will you?”

The victim suffered a lump on his head and a graze on his elbow in what the Crown Prosecution Service said was a “persistent assault”.

MP Mike Amesbury (right) arrives at Chester Ellesmere Port and Neston Magistrates' Court, where he will be sentenced on a charge of assault, after he was found guilty of attacking Paul Fellows in Frodsham, Cheshire, on October 26. Picture date: Monday February 24, 2025. PA Photo. See PA story COURTS Amesbury. Photo credit should read: Peter Byrne/PA Wire
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MP Mike Amesbury outside Chester Ellesmere Port and Neston Magistrates’ Court. Pic: PA

Labour and Reform call for by-election

Amesbury’s future as an MP remains under question as his lawyer indicated he will appeal the sentence.

Otherwise, MPs who receive a custodial sentence, even if it is suspended, automatically trigger a recall petition which could result in a by-election if 10% of constituents sign it.

This will have to wait until the appeal period is over.

Labour suspended Amesbury from the party shortly after the incident, so he has been sitting as an independent.

They have said he will not be admitted back in and called for a by-election, saying his constituents “deserved better” after his “completely unacceptable actions”.

Reform UK also called for Amesbury “to do the honourable thing and resign immediately”.

‘Alarm bells will be ringing’ for PM

Sky News chief political correspondent Jon Craig said while Labour won the seat at last year’s election with a “fairly healthy majority” of more than 14,000, there will be “real nervousness” within the party about holding it.

Reform came second in Runcorn and Helsby at the general election and – given their lead in the national polls – Craig said “alarm bells will be ringing” for Sir Keir Starmer.

Tap here to read Jon Craig’s full analysis.

Mike Amesbury
Image:
Mike Amesbury was captured punching a man on CCTV

‘A necessary punishment’

Sentencing Amesbury, deputy senior district judge Tan Ikram said an immediate custodial sentence was “necessary as a punishment and a deterrent”.

The judge added Amesbury, who has been an MP since 2017, would serve 40% of his sentence in custody and will remain on licence for 12 months after his release.

Amesbury’s lawyer requested the judge return to the court moments after he was taken to the cells by two security guards, as he wanted to make a bail application while they appeal his sentence.

The judge returned to court, sat down, paused briefly and said: “Application refused.”

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Amesbury will be taken to HMP Altcourse in Liverpool. Unlike many defendants, he did not appear to have a bag of belongings with him.

After pleading guilty, he described the incident as “highly regrettable” and apologised to Mr Fellows and his family outside the court.

Alison Storey, senior specialist prosecutor with the Crown Prosecution Service’s special crime division, said Amesbury’s victim did not react aggressively and was alone at the time of the assault.

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How net zero push is impacting Britain’s economy – including some nice salary bumps

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How net zero push is impacting Britain's economy - including some nice salary bumps

The net zero sector has grown by 10% over the past year – adding £83bn to the UK economy, a new study suggests.

Employment in green businesses and industry has also climbed 10%, supporting the equivalent of 951,000 full-time jobs (2.9% of total UK employment).

Politics latest: PM warns of ‘crucial moment’ in Ukraine war

The study – commissioned by thinktank the Energy and Climate Intelligence Unit (ECIU) – found for every £1 of value generated by the net zero economy, an additional £1.89 was created in the wider economy.

It report was published as the government increases efforts to meet a legally binding goal to cut greenhouse gas emissions to zero overall (that’s net zero) by 2050.

Some Conservative and Reform MPs have criticised net zero, electric cars and renewables, suggesting efforts to curb climate change are to blame for higher energy bills and the deindustrialisation of Britain.

But the report, with analysis from CBI Economics and the Data City, suggests the UK’s net zero economy is a significant driver of growth, innovation, and productivity.

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What’s inside Labour’s net zero plan?

Where is the growth happening?

Renewables, electric vehicles, low carbon heating, recycling and green finance are all part of the net zero sector.

Small and medium businesses with fewer than 250 employees are the main drivers of growth, and salaries are 15% higher than the UK average (£43,100, compared with £37,430).

Regions beyond London and the South East are where the net zero economy is growing significantly, the report found, boosting some of the country’s most deprived areas.

The West Midlands, Yorkshire and the Humber, and southwest England were the largest contributors, each more than 5% of the national total, while Scotland’s net zero economy has grown by 21.3% since 2022 – now worth £9.1bn.

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File photo dated 26/07/22 of RWE's Gwynt y Mor, the world's 2nd largest offshore wind farm located eight miles offshore in Liverpool Bay, off the coast of North Wales. Ben Birchall/PA Wire
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RWE’s Gwynt y Mor, off the coast of North Wales, is the world’s fifth largest offshore wind farm. Pic: Ben Birchall/PA

Tyne and Teesside was also highlighted as a hotspot thanks to a £1bn Nissan electric vehicle project, which includes a gigafactory for next-gen batteries. It is creating 6,200 jobs.

London and the South East are still leading the way, with £16.2bn and £13.1bn of green investment respectively.

Overall, the sector attracted £23bn of public, private and foreign direct investment – and each full-time job generated £105,000 in economic value, well above the UK average, the report found.

What are the Conservatives and Reform’s views on net zero?

Tory leader Kemi Badenoch has described herself as a “net zero sceptic” and her voting record shows she has largely opposed efforts to reduce greenhouse gas emissions.

She has also voted against banning fracking and called net zero targets “arbitrary”, saying they would “bankrupt” the UK.

The Conservatives’ manifesto from the 2024 election, when Rishi Sunak was leader, said the party was committed to a “pragmatic and proportionate” approach to net zero by 2050.

It said the party would invest £6bn in energy efficiency over three years to make one million homes warmer.

Reform has said it would impose taxes on the renewable energy sector and wants to scrap “net stupid zero” targets.

The party blames net zero policies for higher energy bills and deindustrialisation in the UK and believe green initiatives will make “zero difference to climate change”.

Deputy leader Richard Tice called renewable energy a “massive con” and promised Reform would recover subsidies paid to wind and solar companies.

‘You can’t have growth without green’

Energy Secretary Ed Miliband said the findings showed “net zero is essential to growth, a strong economy, and money in working people’s pockets”.

Making Britain “a clean energy superpower” will provide “energy security, good jobs, and investment in our communities”, he added.

Louise Hellem, chief economist at the CBI, said “there are huge emerging markets for green technologies that the UK must capitalise on”.

“It is clear, you can’t have growth without green,” she said.

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Friedrich Merz: German chancellor-in-waiting vows to ‘create unity’ in Europe

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Friedrich Merz: German chancellor-in-waiting vows to 'create unity' in Europe

Friedrich Merz, who is set to become the new German chancellor, has vowed to “create unity” in Europe as it adjusts to the new Trump administration and Russia’s war on Ukraine.

Mr Merz’s task will be complicated by the need to form a coalition with the centre-left Social Democrats of outgoing chancellor Olaf Scholz, who will remain in office for the immediate future.

He has repeatedly pledged not to work with the far-right Alternative for Germany (AfD) party, despite its second-place finish but which is under observation by the country’s intelligence agency for suspected right-wing extremism.

Mr Merz’s conservative Christian Democrats and their Bavarian sister party the Christian Social Union, which won with 28.5% of the votes, and the Social Democrats have a combined 328 seats in the 630-seat parliament.

The 69-year-old, who put toughening Germany’s immigration laws at the forefront of the election campaign, said he hopes to complete a deal by Easter.

Experts believe this could prove to be a challenging timescale as the rivals try to find common ground over key policies.

Co-leader of the Social Democrats, Lars Klingbeil, indicated a deal with Mr Merz is not a formality.

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The path to power may not be smooth for Merz

He said: “The ball is in Friedrich Merz’s court. Only the course of any talks will show whether a government can be formed.”

With US President Donald Trump back in the White House and tensions rising over how to resolve the war in Ukraine, Mr Merz wants to unify Europe in the face of challenges from the US and Russia.

“I have no illusions at all about what is happening from America,” he told supporters.

“We are under such massive pressure… my absolute priority now is really to create unity in Europe.”

Read more:
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At a media conference later, he added: “There are three topics we need to talk about. Of course, external and security policy – especially following the statements coming out of Washington.

“It is clear that we as Europeans need to be able to act swiftly. We need to be able to defend ourselves. That is a topic that is a top priority in the next few weeks.”

Mr Merz said he remains “hopeful” of maintaining the transatlantic relationship, but warned if it “is destroyed, it will not only be to the detriment of Europe, it will also be to the detriment of America”.

On the other key issues, he added: “Another important topic is the immigration – that is an area where we have proposals. I suppose the Social Democrats will be prepared to talk to us about this as well.

“The third topic is the economic situation. We have to protect work in the industrial sector in Germany.”

He also earlier used social media to say “Europe stands unwaveringly by Ukraine’s side” and how “we must put Ukraine in a position of strength”.

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